Implement Queue using Stacks Implement the following operations of a queue using stacks. push(x) — Push …

  Find the sum of all left leaves in a given binary tree. Example: 3 / \ 9 20 / \ 15 7 There are two left…

题目描述 Given a string containing only digits, restore it by returning all possible valid IP address combinations…

题目： Given n, generate all structurally unique BST’s (binary search trees) that store valu…

1. 题目 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 2. 思路…

  You are given two arrays (without duplicates) nums1 and nums2 where nums1…

LeetCode 84. Largest Rectangle in Histogram 单调栈应用 leetcode+ 循环数组，求右边第一个大的数字 求一个数组中右边第一个比他大的数（单调栈 LeetCode——寻找数…

24. Swap Nodes in Pairs 题目 Given a linked list, swap every two adjacent nodes and return its head. For example…

  Given an array of integers that is already sorted in ascending order, find two numbers such that they a…

  Given two 1d vectors, implement an iterator to return their elements alternately. For example, given tw…

  Given two strings s1 and s2, write a function to return true if s2 contains th…

  Given the running logs of n functions that are executed in a nonpreemptive single threaded CP…