原文链接: https://leetcode-cn.com/problems/deepest-leaves-sum 英文原文Given the root of a binary tree, return the sum of values of its deepest leaves. Example 1: Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8] Output: 15 Example 2: Input: root = [6,…

原文链接: https://leetcode-cn.com/problems/reverse-subarray-to-maximize-array-value 英文原文You are given an integer array nums. The value of this array is defined as the sum of |nums[i] - nums[i + 1]| for all 0 <= i < nums.length - 1. You are allowed to sel…

原文链接: https://leetcode-cn.com/problems/rank-transform-of-an-array 英文原文Given an array of integers arr, replace each element with its rank. The rank represents how large the element is. The rank has the following rules: Rank is an integer starting from…

原文链接: https://leetcode-cn.com/problems/rank-transform-of-a-matrix 英文原文Given an m x n matrix, return a new matrix answer where answer[row][col] is the rank of matrix[row][col]. The rank is an integer that represents how large an element is compared to…

原文链接: https://leetcode-cn.com/problems/snapshot-array 英文原文Implement a SnapshotArray that supports the following interface: SnapshotArray(int length) initializes an array-like data structure with the given length. Initially, each element equals 0. voi…

原文链接: https://leetcode-cn.com/problems/day-of-the-year 英文原文Given a string date representing a Gregorian calendar date formatted as YYYY-MM-DD, return the day number of the year. Example 1: Input: date = "2019-01-09" Output: 9 Explanation: Given date …

原文链接: https://leetcode-cn.com/problems/swap-for-longest-repeated-character-substring 英文原文You are given a string text. You can swap two of the characters in the text. Return the length of the longest substring with repeated characters. Example 1: Inpu…

原文链接: https://leetcode-cn.com/problems/online-majority-element-in-subarray 英文原文Design a data structure that efficiently finds the majority element of a given subarray. The majority element of a subarray is an element that occurs threshold times or mo…

原文链接: https://leetcode-cn.com/problems/number-of-dice-rolls-with-target-sum 英文原文You have d dice and each die has f faces numbered 1, 2, ..., f. You are given three integers d, f, and target. Return the number of possible ways (out of fd total ways) m…

原文链接: https://leetcode-cn.com/problems/maximum-number-of-words-you-can-type 英文原文There is a malfunctioning keyboard where some letter keys do not work. All other keys on the keyboard work properly. Given a string text of words separated by a single sp…

原文链接: https://leetcode-cn.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list 英文原文Given the head of a linked list, we repeatedly delete consecutive sequences of nodes that sum to 0 until there are no such sequences. After doing so, return…

原文链接: https://leetcode-cn.com/problems/dinner-plate-stacks 英文原文You have an infinite number of stacks arranged in a row and numbered (left to right) from 0, each of the stacks has the same maximum capacity. Implement the DinnerPlates class: DinnerPlat…

原文链接: https://leetcode-cn.com/problems/compare-strings-by-frequency-of-the-smallest-character 英文原文Let the function f(s) be the frequency of the lexicographically smallest character in a non-empty string s. For example, if s = "dcce" then f(s) = 2 bec…

原文链接: https://leetcode-cn.com/problems/number-of-days-between-two-dates 英文原文Write a program to count the number of days between two dates. The two dates are given as strings, their format is YYYY-MM-DD as shown in the examples. Example 1: Input: date…

原文链接: https://leetcode-cn.com/problems/validate-binary-tree-nodes 英文原文You have n binary tree nodes numbered from 0 to n - 1 where node i has two children leftChild[i] and rightChild[i], return true if and only if all the given nodes form exactly one …

原文链接: https://leetcode-cn.com/problems/closest-divisors 英文原文Given an integer num, find the closest two integers in absolute difference whose product equals num + 1 or num + 2. Return the two integers in any order. Example 1: Input: num = 8 Output: [3…

原文链接: https://leetcode-cn.com/problems/largest-multiple-of-three 英文原文Given an array of digits digits, return the largest multiple of three that can be formed by concatenating some of the given digits in any order. If there is no answer return an empt…

原文链接: https://leetcode-cn.com/problems/prime-arrangements 英文原文Return the number of permutations of 1 to n so that prime numbers are at prime indices (1-indexed.) (Recall that an integer is prime if and only if it is greater than 1, and cannot be writ…

原文链接: https://leetcode-cn.com/problems/can-make-palindrome-from-substring 英文原文You are given a string s and array queries where queries[i] = [lefti, righti, ki]. We may rearrange the substring s[lefti...righti] for each query and then choose up to ki …

原文链接: https://leetcode-cn.com/problems/number-of-valid-words-for-each-puzzle 英文原文With respect to a given puzzle string, a word is valid if both the following conditions are satisfied: word contains the first letter of puzzle. For each letter in word,…

原文链接: https://leetcode-cn.com/problems/four-divisors 英文原文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. Example 1: Input: nums…

原文链接: https://leetcode-cn.com/problems/balance-a-binary-search-tree 英文原文Given the root of a binary search tree, return a balanced binary search tree with the same node values. If there is more than one answer, return any of them. A binary search tree…

原文链接: https://leetcode-cn.com/problems/constrained-subsequence-sum 英文原文Given an integer array nums and an integer k, return the maximum sum of a non-empty subsequence of that array such that for every two consecutive integers in the subsequence, nums…

原文链接: https://leetcode-cn.com/problems/distance-between-bus-stops 英文原文A bus has n stops numbered from 0 to n - 1 that form a circle. We know the distance between all pairs of neighboring stops where distance[i] is the distance between the stops numbe…

原文链接: https://leetcode-cn.com/problems/maximum-subarray-sum-with-one-deletion 英文原文Given an array of integers, return the maximum sum for a non-empty subarray (contiguous elements) with at most one element deletion. In other words, you want to choose …

原文链接: https://leetcode-cn.com/problems/make-array-strictly-increasing 英文原文Given two integer arrays arr1 and arr2, return the minimum number of operations (possibly zero) needed to make arr1 strictly increasing. In one operation, you can choose two in…

原文链接: https://leetcode-cn.com/problems/day-of-the-week 英文原文Given a date, return the corresponding day of the week for that date. The input is given as three integers representing the day, month and year respectively. Return the answer as one of the f…

原文链接: https://leetcode-cn.com/problems/three-consecutive-odds 英文原文Given an integer array arr, return true if there are three consecutive odd numbers in the array. Otherwise, return false. Example 1: Input: arr = [2,6,4,1] Output: false Explanation: T…

原文链接: https://leetcode-cn.com/problems/kth-ancestor-of-a-tree-node 英文原文You are given a tree with n nodes numbered from 0 to n - 1 in the form of a parent array parent where parent[i] is the parent of ith node. The root of the tree is node 0. Find the…

原文链接: https://leetcode-cn.com/problems/minimum-garden-perimeter-to-collect-enough-apples 英文原文In a garden represented as an infinite 2D grid, there is an apple tree planted at every integer coordinate. The apple tree planted at an integer coordinate (…