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You are given a 2D integer array intervals where intervals[i] = [lefti, righti] represents the inclusive interval [lefti, righti]. You have to divide the intervals into one or more groups such that each interval is in exactly one group, and no two intervals that are in the same group intersect each other. Return the minimum number of groups you need to make. Two intervals intersect if there is at least one common number between them. For example, the intervals [1, 5] and [5, 8] intersect.

Input: intervals = [[5,10],[6,8],[1,5],[2,3],[1,10]] Output: 3

You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Input: n = 2 Output: 2

There is an undirected connected tree with n nodes labeled from 0 to n - 1 and n - 1 edges. You are given a 0-indexed integer array nums of length n where nums[i] represents the value of the ith node. You are also given a 2D integer array edges of length n - 1 where edges[i] = [ai, bi] indicates that there is an edge between nodes ai and bi in the tree. Remove two distinct edges of the tree to form three connected components. For a pair of removed edges, the following steps are defined: Get the XOR of all the values of the nodes for each of the three components respectively. The difference between the largest XOR value and the smallest XOR value is the score of the pair. For example, say the three components have the node values: [4,5,7], [1,9], and [3,3,3]. The three XOR values are 4 ^ 5 ^ 7 = 6, 1 ^ 9 = 8, and 3 ^ 3 ^ 3 = 3. The largest XOR value is 8 and the smallest XOR value is 3. The score is then 8 - 3 = 5. Return the minimum score of any possible pair of edge removals on the given tree.

Input: nums = [1,5,5,4,11], edges = [[0,1],[1,2],[1,3],[3,4]] Output: 9

There is a broken calculator that has the integer startValue on its display initially. In one operation, you can: multiply the number on display by 2, or subtract 1 from the number on display. Given two integers startValue and target, return the minimum number of operations needed to display target on the calculator.

Input: startValue = 2, target = 3 Output: 2

Given an integer n, return the number of structurally unique BST's (binary search trees) which has exactly n nodes of unique values from 1 to n.

Input: n = 3 Output: 5 Example 2: Input: n = 1 Output: 1 Constraints: 1 <= n <= 1

You are given a 0-indexed m x n integer matrix grid and an integer k. You are currently at position (0, 0) and you want to reach position (m - 1, n - 1) moving only down or right. Return the number of paths where the sum of the elements on the path is divisible by k. Since the answer may be very large, return it modulo 109 + 7.

Input: grid = [[5,2,4],[3,0,5],[0,7,2]], k = 3 Output: 2

Given n points on a 1-D plane, where the ith point (from 0 to n-1) is at x = i, find the number of ways we can draw exactly k non-overlapping line segments such that each segment covers two or more points. The endpoints of each segment must have integral coordinates. The k line segments do not have to cover all n points, and they are allowed to share endpoints. Return the number of ways we can draw k non-overlapping line segments. Since this number can be huge, return it modulo 109 + 7.

Input: n = 4, k = 2 Output: 5

The thief has found himself a new place for his thievery again. There is only one entrance to this area, called root. Besides the root, each house has one and only one parent house. After a tour, the smart thief realized that all houses in this place form a binary tree. It will automatically contact the police if two directly-linked houses were broken into on the same night. Given the root of the binary tree, return the maximum amount of money the thief can rob without alerting the police.

Input: root = [3,2,3,null,3,null,1] Output: 7

Given an integer array nums, return the sum of divisors of the integers in that array that have exactly four divisors. If there is no such integer in the array, return 0.

Input: nums = [21,4,7] Output: 32

Given a binary tree where node values are digits from 1 to 9. A path in the binary tree is said to be pseudo-palindromic if at least one permutation of the node values in the path is a palindrome. Return the number of pseudo-palindromic paths going from the root node to leaf nodes.

Input: root = [2,3,1,3,1,null,1] Output: 2

You are given an integer array cost where cost[i] is the cost of ith step on a staircase. Once you pay the cost, you can either climb one or two steps. You can either start from the step with index 0, or the step with index 1. Return the minimum cost to reach the top of the floor.

Input: cost = [10,15,20] Output: 15

Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string. Note: You must not use any built-in BigInteger library or convert the inputs to integer directly.

Input: num1 = "2", num2 = "3" Output: "6" Example 2: Input: num1 = "123", num2 = "456" Output: "56088" Constraints: 1 <= num1.length, num2.length <= 200 num1 and num2 consist of digits only. Both num1 and num2 do not contain any leading zero, except the number 0 itself

Given a string word to which you can insert letters "a", "b" or "c" anywhere and any number of times, return the minimum number of letters that must be inserted so that word becomes valid. A string is called valid if it can be formed by concatenating the string "abc" several times.

Input: word = "b" Output: 2

You are given a large sample of integers in the range [0, 255]. Since the sample is so large, it is represented by an array count where count[k] is the number of times that k appears in the sample. Calculate the following statistics: minimum: The minimum element in the sample. maximum: The maximum element in the sample. mean: The average of the sample, calculated as the total sum of all elements divided by the total number of elements. median: If the sample has an odd number of elements, then the median is the middle element once the sample is sorted. If the sample has an even number of elements, then the median is the average of the two middle elements once the sample is sorted. mode: The number that appears the most in the sample. It is guaranteed to be unique. Return the statistics of the sample as an array of floating-point numbers [minimum, maximum, mean, median, mode]. Answers within 10-5 of the actual answer will be accepted.

Input: count = [0,1,3,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] Output: [1.00000,3.00000,2.37500,2.50000,3.00000]

You would like to make dessert and are preparing to buy the ingredients. You have n ice cream base flavors and m types of toppings to choose from. You must follow these rules when making your dessert: There must be exactly one ice cream base. You can add one or more types of topping or have no toppings at all. There are at most two of each type of topping. You are given three inputs: baseCosts, an integer array of length n, where each baseCosts[i] represents the price of the ith ice cream base flavor. toppingCosts, an integer array of length m, where each toppingCosts[i] is the price of one of the ith topping. target, an integer representing your target price for dessert. You want to make a dessert with a total cost as close to target as possible. Return the closest possible cost of the dessert to target. If there are multiple, return the lower one.

Input: baseCosts = [1,7], toppingCosts = [3,4], target = 10 Output: 10

The Tribonacci sequence Tn is defined as follows: T0 = 0, T1 = 1, T2 = 1, and Tn+3 = Tn + Tn+1 + Tn+2 for n >= 0. Given n, return the value of Tn.

Input: n = 4 Output: 4

There is a 3 lane road of length n that consists of n + 1 points labeled from 0 to n. A frog starts at point 0 in the second lane and wants to jump to point n. However, there could be obstacles along the way. You are given an array obstacles of length n + 1 where each obstacles[i] (ranging from 0 to 3) describes an obstacle on the lane obstacles[i] at point i. If obstacles[i] == 0, there are no obstacles at point i. There will be at most one obstacle in the 3 lanes at each point. For example, if obstacles[2] == 1, then there is an obstacle on lane 1 at point 2. The frog can only travel from point i to point i + 1 on the same lane if there is not an obstacle on the lane at point i + 1. To avoid obstacles, the frog can also perform a side jump to jump to another lane (even if they are not adjacent) at the same point if there is no obstacle on the new lane. For example, the frog can jump from lane 3 at point 3 to lane 1 at point 3. Return the minimum number of side jumps the frog needs to reach any lane at point n starting from lane 2 at point 0. Note: There will be no obstacles on points 0 and n.

Input: obstacles = [0,1,2,3,0] Output: 2

You are given an m x n matrix maze (0-indexed) with empty cells (represented as '.') and walls (represented as '+'). You are also given the entrance of the maze, where entrance = [entrancerow, entrancecol] denotes the row and column of the cell you are initially standing at. In one step, you can move one cell up, down, left, or right. You cannot step into a cell with a wall, and you cannot step outside the maze. Your goal is to find the nearest exit from the entrance. An exit is defined as an empty cell that is at the border of the maze. The entrance does not count as an exit. Return the number of steps in the shortest path from the entrance to the nearest exit, or -1 if no such path exists.

Input: maze = [["+","+",".","+"],[".",".",".","+"],["+","+","+","."]], entrance = [1,2] Output: 1

Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.

Input: n = 13 Output: 6 Example 2: Input: n = 0 Output: 0 Constraints: 0 <= n <= 10

You are given a binary string s and a positive integer k. Return the length of the longest subsequence of s that makes up a binary number less than or equal to k. Note: The subsequence can contain leading zeroes. The empty string is considered to be equal to 0. A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.

Input: s = "1001010", k = 5 Output: 5

Given a string s which consists of lowercase or uppercase letters, return the length of the longest palindrome that can be built with those letters. Letters are case sensitive, for example, "Aa" is not considered a palindrome here.

Input: s = "abccccdd" Output: 7

Given the root of a binary tree, return the most frequent subtree sum. If there is a tie, return all the values with the highest frequency in any order. The subtree sum of a node is defined as the sum of all the node values formed by the subtree rooted at that node (including the node itself).

Input: root = [5,2,-3] Output: [2,-3,4] Example 2: Input: root = [5,2,-5] Output: [2] Constraints: The number of nodes in the tree is in the range [1, 104]. -105 <= Node.val <= 10

You are given a positive integer n. Each digit of n has a sign according to the following rules: The most significant digit is assigned a positive sign. Each other digit has an opposite sign to its adjacent digits. Return the sum of all digits with their corresponding sign.

Input: n = 521 Output: 4

You have a convex n-sided polygon where each vertex has an integer value. You are given an integer array values where values[i] is the value of the ith vertex (i.e., clockwise order). You will triangulate the polygon into n - 2 triangles. For each triangle, the value of that triangle is the product of the values of its vertices, and the total score of the triangulation is the sum of these values over all n - 2 triangles in the triangulation. Return the smallest possible total score that you can achieve with some triangulation of the polygon.

Input: values = [1,2,3] Output: 6

Given an array of distinct integers nums and a target integer target, return the number of possible combinations that add up to target. The test cases are generated so that the answer can fit in a 32-bit integer.

Input: nums = [1,2,3], target = 4 Output: 7

An n x n grid is composed of 1 x 1 squares where each 1 x 1 square consists of a '/', '\', or blank space ' '. These characters divide the square into contiguous regions. Given the grid grid represented as a string array, return the number of regions. Note that backslash characters are escaped, so a '\' is represented as '\\'.

Input: grid = [" /","/ "] Output: 2 Example 2: Input: grid = [" /"," "] Output: 1 Example 3: Input: grid = ["/\\","\\/"] Output: 5

You are given two 0-indexed integer arrays nums1 and nums2, of equal length n. In one operation, you can swap the values of any two indices of nums1. The cost of this operation is the sum of the indices. Find the minimum total cost of performing the given operation any number of times such that nums1[i] != nums2[i] for all 0 <= i <= n - 1 after performing all the operations. Return the minimum total cost such that nums1 and nums2 satisfy the above condition. In case it is not possible, return -1.

Input: nums1 = [1,2,3,4,5], nums2 = [1,2,3,4,5] Output: 10

Your task is to calculate ab mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array.

Input: a = 2, b = [3] Output: 8 Example 2: Input: a = 2, b = [1,0] Output: 1024 Example 3: Input: a = 1, b = [4,3,3,8,5,2] Output: 1 Constraints: 1 <= a <= 231 - 1 1 <= b.length <= 2000 0 <= b[i] <= 9 b does not contain leading zeros

The array-form of an integer num is an array representing its digits in left to right order. For example, for num = 1321, the array form is [1,3,2,1]. Given num, the array-form of an integer, and an integer k, return the array-form of the integer num + k.

Input: num = [1,2,0,0], k = 34 Output: [1,2,3,4]

Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

Input: grid = [ ["1","1","1","1","0"], ["1","1","0","1","0"], ["1","1","0","0","0"], ["0","0","0","0","0"] ] Output: 1 Example 2: Input: grid = [ ["1","1","0","0","0"], ["1","1","0","0","0"], ["0","0","1","0","0"], ["0","0","0","1","1"] ] Output: 3 Constraints: m == grid.length n == grid[i].length 1 <= m, n <= 300 grid[i][j] is '0' or '1'

An array is squareful if the sum of every pair of adjacent elements is a perfect square. Given an integer array nums, return the number of permutations of nums that are squareful. Two permutations perm1 and perm2 are different if there is some index i such that perm1[i] != perm2[i].

Input: nums = [1,17,8] Output: 2

Alice and Bob continue their games with piles of stones. There are a number of piles arranged in a row, and each pile has a positive integer number of stones piles[i]. The objective of the game is to end with the most stones. Alice and Bob take turns, with Alice starting first. Initially, M = 1. On each player's turn, that player can take all the stones in the first X remaining piles, where 1 <= X <= 2M. Then, we set M = max(M, X). The game continues until all the stones have been taken. Assuming Alice and Bob play optimally, return the maximum number of stones Alice can get.

Input: piles = [2,7,9,4,4] Output: 10

A binary tree is uni-valued if every node in the tree has the same value. Given the root of a binary tree, return true if the given tree is uni-valued, or false otherwise.

Input: root = [1,1,1,1,1,null,1] Output: true Example 2: Input: root = [2,2,2,5,2] Output: false Constraints: The number of nodes in the tree is in the range [1, 100]. 0 <= Node.val < 10

You are given two strings s and p where p is a subsequence of s. You are also given a distinct 0-indexed integer array removable containing a subset of indices of s (s is also 0-indexed). You want to choose an integer k (0 <= k <= removable.length) such that, after removing k characters from s using the first k indices in removable, p is still a subsequence of s. More formally, you will mark the character at s[removable[i]] for each 0 <= i < k, then remove all marked characters and check if p is still a subsequence. Return the maximum k you can choose such that p is still a subsequence of s after the removals. A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.

Input: s = "abcacb", p = "ab", removable = [3,1,0] Output: 2

Given the root of a binary search tree and the lowest and highest boundaries as low and high, trim the tree so that all its elements lies in [low, high]. Trimming the tree should not change the relative structure of the elements that will remain in the tree (i.e., any node's descendant should remain a descendant). It can be proven that there is a unique answer. Return the root of the trimmed binary search tree. Note that the root may change depending on the given bounds.

Input: root = [1,0,2], low = 1, high = 2 Output: [1,null,2] Example 2: Input: root = [3,0,4,null,2,null,null,1], low = 1, high = 3 Output: [3,2,null,1] Constraints: The number of nodes in the tree is in the range [1, 104]. 0 <= Node.val <= 104 The value of each node in the tree is unique. root is guaranteed to be a valid binary search tree. 0 <= low <= high <= 10

Given the coordinates of two rectilinear rectangles in a 2D plane, return the total area covered by the two rectangles. The first rectangle is defined by its bottom-left corner (ax1, ay1) and its top-right corner (ax2, ay2). The second rectangle is defined by its bottom-left corner (bx1, by1) and its top-right corner (bx2, by2).

Input: ax1 = -3, ay1 = 0, ax2 = 3, ay2 = 4, bx1 = 0, by1 = -1, bx2 = 9, by2 = 2 Output: 45 Example 2: Input: ax1 = -2, ay1 = -2, ax2 = 2, ay2 = 2, bx1 = -2, by1 = -2, bx2 = 2, by2 = 2 Output: 16 Constraints: -104 <= ax1 <= ax2 <= 104 -104 <= ay1 <= ay2 <= 104 -104 <= bx1 <= bx2 <= 104 -104 <= by1 <= by2 <= 10

There are n people standing in a line labeled from 1 to n. The first person in the line is holding a pillow initially. Every second, the person holding the pillow passes it to the next person standing in the line. Once the pillow reaches the end of the line, the direction changes, and people continue passing the pillow in the opposite direction. For example, once the pillow reaches the nth person they pass it to the n - 1th person, then to the n - 2th person and so on. Given the two positive integers n and time, return the index of the person holding the pillow after time seconds.

Input: n = 4, time = 5 Output: 2

You are given a string s, a string chars of distinct characters and an integer array vals of the same length as chars. The cost of the substring is the sum of the values of each character in the substring. The cost of an empty string is considered 0. The value of the character is defined in the following way: If the character is not in the string chars, then its value is its corresponding position (1-indexed) in the alphabet. For example, the value of 'a' is 1, the value of 'b' is 2, and so on. The value of 'z' is 26. Otherwise, assuming i is the index where the character occurs in the string chars, then its value is vals[i]. Return the maximum cost among all substrings of the string s.

Input: s = "adaa", chars = "d", vals = [-1000] Output: 2

Given two positive integers a and b, return the number of common factors of a and b. An integer x is a common factor of a and b if x divides both a and b.

Input: a = 12, b = 6 Output: 4

Given an integer n, return true if it is possible to represent n as the sum of distinct powers of three. Otherwise, return false. An integer y is a power of three if there exists an integer x such that y == 3x.

Input: n = 12 Output: true

Given a string s, return the longest palindromic substring in s.

Input: s = "babad" Output: "bab"

Serialization is converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment. Design an algorithm to serialize and deserialize a binary search tree. There is no restriction on how your serialization/deserialization algorithm should work. You need to ensure that a binary search tree can be serialized to a string, and this string can be deserialized to the original tree structure. The encoded string should be as compact as possible.

Input: root = [2,1,3] Output: [2,1,3] Example 2: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 104]. 0 <= Node.val <= 104 The input tree is guaranteed to be a binary search tree

You are assigned to put some amount of boxes onto one truck. You are given a 2D array boxTypes, where boxTypes[i] = [numberOfBoxesi, numberOfUnitsPerBoxi]: numberOfBoxesi is the number of boxes of type i. numberOfUnitsPerBoxi is the number of units in each box of the type i. You are also given an integer truckSize, which is the maximum number of boxes that can be put on the truck. You can choose any boxes to put on the truck as long as the number of boxes does not exceed truckSize. Return the maximum total number of units that can be put on the truck.

Input: boxTypes = [[1,3],[2,2],[3,1]], truckSize = 4 Output: 8

There are 3n piles of coins of varying size, you and your friends will take piles of coins as follows: In each step, you will choose any 3 piles of coins (not necessarily consecutive). Of your choice, Alice will pick the pile with the maximum number of coins. You will pick the next pile with the maximum number of coins. Your friend Bob will pick the last pile. Repeat until there are no more piles of coins. Given an array of integers piles where piles[i] is the number of coins in the ith pile. Return the maximum number of coins that you can have.

Input: piles = [2,4,1,2,7,8] Output: 9

You are given the root of a binary tree. A ZigZag path for a binary tree is defined as follow: Choose any node in the binary tree and a direction (right or left). If the current direction is right, move to the right child of the current node; otherwise, move to the left child. Change the direction from right to left or from left to right. Repeat the second and third steps until you can't move in the tree. Zigzag length is defined as the number of nodes visited - 1. (A single node has a length of 0). Return the longest ZigZag path contained in that tree.

Input: root = [1,null,1,1,1,null,null,1,1,null,1,null,null,null,1] Output: 3

You are given a 2D integer array rectangles where rectangles[i] = [li, hi] indicates that ith rectangle has a length of li and a height of hi. You are also given a 2D integer array points where points[j] = [xj, yj] is a point with coordinates (xj, yj). The ith rectangle has its bottom-left corner point at the coordinates (0, 0) and its top-right corner point at (li, hi). Return an integer array count of length points.length where count[j] is the number of rectangles that contain the jth point. The ith rectangle contains the jth point if 0 <= xj <= li and 0 <= yj <= hi. Note that points that lie on the edges of a rectangle are also considered to be contained by that rectangle.

Input: rectangles = [[1,2],[2,3],[2,5]], points = [[2,1],[1,4]] Output: [2,1]

In a row of dominoes, tops[i] and bottoms[i] represent the top and bottom halves of the ith domino. (A domino is a tile with two numbers from 1 to 6 - one on each half of the tile.) We may rotate the ith domino, so that tops[i] and bottoms[i] swap values. Return the minimum number of rotations so that all the values in tops are the same, or all the values in bottoms are the same. If it cannot be done, return -1.

Input: tops = [2,1,2,4,2,2], bottoms = [5,2,6,2,3,2] Output: 2

Given the root of a Binary Search Tree (BST), return the minimum difference between the values of any two different nodes in the tree.

Input: root = [4,2,6,1,3] Output: 1 Example 2: Input: root = [1,0,48,null,null,12,49] Output: 1 Constraints: The number of nodes in the tree is in the range [2, 100]. 0 <= Node.val <= 105 Note: This question is the same as 530: https://leetcode.com/problems/minimum-absolute-difference-in-bst

You are given an m x n grid. Each cell of grid represents a street. The street of grid[i][j] can be: 1 which means a street connecting the left cell and the right cell. 2 which means a street connecting the upper cell and the lower cell. 3 which means a street connecting the left cell and the lower cell. 4 which means a street connecting the right cell and the lower cell. 5 which means a street connecting the left cell and the upper cell. 6 which means a street connecting the right cell and the upper cell. You will initially start at the street of the upper-left cell (0, 0). A valid path in the grid is a path that starts from the upper left cell (0, 0) and ends at the bottom-right cell (m - 1, n - 1). The path should only follow the streets. Notice that you are not allowed to change any street. Return true if there is a valid path in the grid or false otherwise.

Input: grid = [[2,4,3],[6,5,2]] Output: true

You are given an integer array nums and an integer k. Split the array into some number of non-empty subarrays. The cost of a split is the sum of the importance value of each subarray in the split. Let trimmed(subarray) be the version of the subarray where all numbers which appear only once are removed. For example, trimmed([3,1,2,4,3,4]) = [3,4,3,4]. The importance value of a subarray is k + trimmed(subarray).length. For example, if a subarray is [1,2,3,3,3,4,4], then trimmed([1,2,3,3,3,4,4]) = [3,3,3,4,4].The importance value of this subarray will be k + 5. Return the minimum possible cost of a split of nums. A subarray is a contiguous non-empty sequence of elements within an array.

Input: nums = [1,2,1,2,1,3,3], k = 2 Output: 8

Given an integer array nums and two integers lower and upper, return the number of range sums that lie in [lower, upper] inclusive. Range sum S(i, j) is defined as the sum of the elements in nums between indices i and j inclusive, where i <= j.

Input: nums = [-2,5,-1], lower = -2, upper = 2 Output: 3

Given the root of a complete binary tree, return the number of the nodes in the tree. According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclusive at the last level h. Design an algorithm that runs in less than O(n) time complexity.

Input: root = [1,2,3,4,5,6] Output: 6 Example 2: Input: root = [] Output: 0 Example 3: Input: root = [1] Output: 1 Constraints: The number of nodes in the tree is in the range [0, 5 * 104]. 0 <= Node.val <= 5 * 104 The tree is guaranteed to be complete

You are given a 0-indexed m x n binary matrix land where a 0 represents a hectare of forested land and a 1 represents a hectare of farmland. To keep the land organized, there are designated rectangular areas of hectares that consist entirely of farmland. These rectangular areas are called groups. No two groups are adjacent, meaning farmland in one group is not four-directionally adjacent to another farmland in a different group. land can be represented by a coordinate system where the top left corner of land is (0, 0) and the bottom right corner of land is (m-1, n-1). Find the coordinates of the top left and bottom right corner of each group of farmland. A group of farmland with a top left corner at (r1, c1) and a bottom right corner at (r2, c2) is represented by the 4-length array [r1, c1, r2, c2]. Return a 2D array containing the 4-length arrays described above for each group of farmland in land. If there are no groups of farmland, return an empty array. You may return the answer in any order.

Input: land = [[1,0,0],[0,1,1],[0,1,1]] Output: [[0,0,0,0],[1,1,2,2]]

There is a set of n items. You are given two integer arrays values and labels where the value and the label of the ith element are values[i] and labels[i] respectively. You are also given two integers numWanted and useLimit. Choose a subset s of the n elements such that: The size of the subset s is less than or equal to numWanted. There are at most useLimit items with the same label in s. The score of a subset is the sum of the values in the subset. Return the maximum score of a subset s.

Input: values = [5,4,3,2,1], labels = [1,1,2,2,3], numWanted = 3, useLimit = 1 Output: 9

You are given two integers n and maxValue, which are used to describe an ideal array. A 0-indexed integer array arr of length n is considered ideal if the following conditions hold: Every arr[i] is a value from 1 to maxValue, for 0 <= i < n. Every arr[i] is divisible by arr[i - 1], for 0 < i < n. Return the number of distinct ideal arrays of length n. Since the answer may be very large, return it modulo 109 + 7.

Input: n = 2, maxValue = 5 Output: 10

Given two positive integers num1 and num2, find the positive integer x such that: x has the same number of set bits as num2, and The value x XOR num1 is minimal. Note that XOR is the bitwise XOR operation. Return the integer x. The test cases are generated such that x is uniquely determined. The number of set bits of an integer is the number of 1's in its binary representation.

Input: num1 = 3, num2 = 5 Output: 3

Given the root of a binary tree, return the lowest common ancestor of its deepest leaves. Recall that: The node of a binary tree is a leaf if and only if it has no children The depth of the root of the tree is 0. if the depth of a node is d, the depth of each of its children is d + 1. The lowest common ancestor of a set S of nodes, is the node A with the largest depth such that every node in S is in the subtree with root A.

Input: root = [3,5,1,6,2,0,8,null,null,7,4] Output: [2,7,4]

We have n cities labeled from 1 to n. Two different cities with labels x and y are directly connected by a bidirectional road if and only if x and y share a common divisor strictly greater than some threshold. More formally, cities with labels x and y have a road between them if there exists an integer z such that all of the following are true: x % z == 0, y % z == 0, and z > threshold. Given the two integers, n and threshold, and an array of queries, you must determine for each queries[i] = [ai, bi] if cities ai and bi are connected directly or indirectly. (i.e. there is some path between them). Return an array answer, where answer.length == queries.length and answer[i] is true if for the ith query, there is a path between ai and bi, or answer[i] is false if there is no path.

Input: n = 6, threshold = 2, queries = [[1,4],[2,5],[3,6]] Output: [false,false,true]

You are given two strings current and correct representing two 24-hour times. 24-hour times are formatted as "HH:MM", where HH is between 00 and 23, and MM is between 00 and 59. The earliest 24-hour time is 00:00, and the latest is 23:59. In one operation you can increase the time current by 1, 5, 15, or 60 minutes. You can perform this operation any number of times. Return the minimum number of operations needed to convert current to correct.

Input: current = "02:30", correct = "04:35" Output: 3

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6

The frequency of an element is the number of times it occurs in an array. You are given an integer array nums and an integer k. In one operation, you can choose an index of nums and increment the element at that index by 1. Return the maximum possible frequency of an element after performing at most k operations.

Input: nums = [1,2,4], k = 5 Output: 3

Given an integer array nums with possible duplicates, randomly output the index of a given target number. You can assume that the given target number must exist in the array. Implement the Solution class: Solution(int[] nums) Initializes the object with the array nums. int pick(int target) Picks a random index i from nums where nums[i] == target. If there are multiple valid i's, then each index should have an equal probability of returning.

Input ["Solution", "pick", "pick", "pick"] [[[1, 2, 3, 3, 3]], [3], [1], [3]] Output [null, 4, 0, 2]

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, 2 is written as II in Roman numeral, just two one's added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II. Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used: I can be placed before V (5) and X (10) to make 4 and 9. X can be placed before L (50) and C (100) to make 40 and 90. C can be placed before D (500) and M (1000) to make 400 and 900. Given an integer, convert it to a roman numeral.

Input: num = 3 Output: "III"

You are given an m x n integer matrix matrix with the following two properties: Each row is sorted in non-decreasing order. The first integer of each row is greater than the last integer of the previous row. Given an integer target, return true if target is in matrix or false otherwise. You must write a solution in O(log(m * n)) time complexity.

Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3 Output: true Example 2: Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13 Output: false Constraints: m == matrix.length n == matrix[i].length 1 <= m, n <= 100 -104 <= matrix[i][j], target <= 10

You are given a 0-indexed integer array nums and an integer k. Your task is to perform the following operation exactly k times in order to maximize your score: Select an element m from nums. Remove the selected element m from the array. Add a new element with a value of m + 1 to the array. Increase your score by m. Return the maximum score you can achieve after performing the operation exactly k times.

Input: nums = [1,2,3,4,5], k = 3 Output: 18

Given an m x n binary matrix mat, return the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1.

Input: mat = [[0,0,0],[0,1,0],[0,0,0]] Output: [[0,0,0],[0,1,0],[0,0,0]] Example 2: Input: mat = [[0,0,0],[0,1,0],[1,1,1]] Output: [[0,0,0],[0,1,0],[1,2,1]] Constraints: m == mat.length n == mat[i].length 1 <= m, n <= 104 1 <= m * n <= 104 mat[i][j] is either 0 or 1. There is at least one 0 in mat

Given a binary tree root and a linked list with head as the first node. Return True if all the elements in the linked list starting from the head correspond to some downward path connected in the binary tree otherwise return False. In this context downward path means a path that starts at some node and goes downwards.

Input: head = [4,2,8], root = [1,4,4,null,2,2,null,1,null,6,8,null,null,null,null,1,3] Output: true

Given the root of a binary tree, return the bottom-up level order traversal of its nodes' values. (i.e., from left to right, level by level from leaf to root).

Input: root = [3,9,20,null,null,15,7] Output: [[15,7],[9,20],[3]] Example 2: Input: root = [1] Output: [[1]] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 2000]. -1000 <= Node.val <= 100

You have a list arr of all integers in the range [1, n] sorted in a strictly increasing order. Apply the following algorithm on arr: Starting from left to right, remove the first number and every other number afterward until you reach the end of the list. Repeat the previous step again, but this time from right to left, remove the rightmost number and every other number from the remaining numbers. Keep repeating the steps again, alternating left to right and right to left, until a single number remains. Given the integer n, return the last number that remains in arr.

Input: n = 9 Output: 6

Bob is standing at cell (0, 0), and he wants to reach destination: (row, column). He can only travel right and down. You are going to help Bob by providing instructions for him to reach destination. The instructions are represented as a string, where each character is either: 'H', meaning move horizontally (go right), or 'V', meaning move vertically (go down). Multiple instructions will lead Bob to destination. For example, if destination is (2, 3), both "HHHVV" and "HVHVH" are valid instructions. However, Bob is very picky. Bob has a lucky number k, and he wants the kth lexicographically smallest instructions that will lead him to destination. k is 1-indexed. Given an integer array destination and an integer k, return the kth lexicographically smallest instructions that will take Bob to destination.

Input: destination = [2,3], k = 1 Output: "HHHVV"

In a warehouse, there is a row of barcodes, where the ith barcode is barcodes[i]. Rearrange the barcodes so that no two adjacent barcodes are equal. You may return any answer, and it is guaranteed an answer exists.

Input: barcodes = [1,1,1,2,2,2] Output: [2,1,2,1,2,1] Example 2: Input: barcodes = [1,1,1,1,2,2,3,3] Output: [1,3,1,3,1,2,1,2] Constraints: 1 <= barcodes.length <= 10000 1 <= barcodes[i] <= 1000

Given a string num that contains only digits and an integer target, return all possibilities to insert the binary operators '+', '-', and/or '*' between the digits of num so that the resultant expression evaluates to the target value. Note that operands in the returned expressions should not contain leading zeros.

Input: num = "123", target = 6 Output: ["1*2*3","1+2+3"]

There is a forest with an unknown number of rabbits. We asked n rabbits "How many rabbits have the same color as you?" and collected the answers in an integer array answers where answers[i] is the answer of the ith rabbit. Given the array answers, return the minimum number of rabbits that could be in the forest.

Input: answers = [1,1,2] Output: 5

We run a preorder depth-first search (DFS) on the root of a binary tree. At each node in this traversal, we output D dashes (where D is the depth of this node), then we output the value of this node. If the depth of a node is D, the depth of its immediate child is D + 1. The depth of the root node is 0. If a node has only one child, that child is guaranteed to be the left child. Given the output traversal of this traversal, recover the tree and return its root.

Input: traversal = "1-2--3--4-5--6--7" Output: [1,2,5,3,4,6,7] Example 2: Input: traversal = "1-2--3---4-5--6---7" Output: [1,2,5,3,null,6,null,4,null,7] Example 3: Input: traversal = "1-401--349---90--88" Output: [1,401,null,349,88,90] Constraints: The number of nodes in the original tree is in the range [1, 1000]. 1 <= Node.val <= 10

Given a string of digits s, return the number of palindromic subsequences of s having length 5. Since the answer may be very large, return it modulo 109 + 7. Note: A string is palindromic if it reads the same forward and backward. A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.

Input: s = "103301" Output: 2

You are given a series of video clips from a sporting event that lasted time seconds. These video clips can be overlapping with each other and have varying lengths. Each video clip is described by an array clips where clips[i] = [starti, endi] indicates that the ith clip started at starti and ended at endi. We can cut these clips into segments freely. For example, a clip [0, 7] can be cut into segments [0, 1] + [1, 3] + [3, 7]. Return the minimum number of clips needed so that we can cut the clips into segments that cover the entire sporting event [0, time]. If the task is impossible, return -1.

Input: clips = [[0,2],[4,6],[8,10],[1,9],[1,5],[5,9]], time = 10 Output: 3

You are given a 0-indexed m x n integer matrix grid consisting of distinct integers from 0 to m * n - 1. You can move in this matrix from a cell to any other cell in the next row. That is, if you are in cell (x, y) such that x < m - 1, you can move to any of the cells (x + 1, 0), (x + 1, 1), ..., (x + 1, n - 1). Note that it is not possible to move from cells in the last row. Each possible move has a cost given by a 0-indexed 2D array moveCost of size (m * n) x n, where moveCost[i][j] is the cost of moving from a cell with value i to a cell in column j of the next row. The cost of moving from cells in the last row of grid can be ignored. The cost of a path in grid is the sum of all values of cells visited plus the sum of costs of all the moves made. Return the minimum cost of a path that starts from any cell in the first row and ends at any cell in the last row.

Input: grid = [[5,3],[4,0],[2,1]], moveCost = [[9,8],[1,5],[10,12],[18,6],[2,4],[14,3]] Output: 17