题目： Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For exa…

题目： Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a nu…

题目： Given two binary strings, return their sum (also a binary string). For example, a = "11" b = "1"…

  Write a SQL query to find all numbers that appear at least three times consecutively. +----+-----+ | Id…

题目： Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substring…

Find Intersection of Two Sets 暴力法 复杂度 时间 O(NM) 空间 O(1) 思路 暴力解法，对于每个在集合1中的元素，我们遍历一遍集合2看看是否存在，如果存在则是Intersection…

Reverse Words in a String Given an input string, reverse the string word by word. For example, Given s = ̶…

  Given an m x n matrix of non-negative integers representing the height of each unit cell in a continent…

  Given a sorted array, two integers k and x, find the k closest elements to&nbs…

题目地址：https://leetcode-cn.com/probl…题目描述：给定一个可包含重复数字的序列，返回所有不重复的全排列。 示例: 输入: [1,1,2]输出:[ [1,1,2], [1,2,1]…

  Given a picture consisting of black and white pixels, find the number of black lonely pixels.…

题目： Sort a linked list in  O ( n  log  n ) time using constant space complexity. 思路： 合并排序法。 代码：…