题目： Merge two sorted linked lists and return it as a new list. The new list should be made by splicing togethe…

Word Pattern Given a pattern and a string str, find if str follows the same pattern. Examples: pattern = "abba…

1. 题目 Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 2. 思路 如果是负数，先…

题目地址：https://leetcode-cn.com/probl…题目描述：给定一个包含 0 和 1 的二维网格地图，其中 1 表示陆地 0 表示水域。 网格中的格子水平和垂直方向相连（对角线方向不相连）…

  Given an array of non-negative integers, you are initially positioned at the first index of the array. …

  Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For…

  Find the nth digit of the infinite integer sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, … Note: n …

  Given an integer array, return the k-th smallest distance among all the pairs. The distance o…

Shortest Palindrome Given a string S, you are allowed to convert it to a palindrome by adding characters in fr…

1. 题目 Given an array with n objects colored red, white or blue, sort them so that objects of the same color ar…

  There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off…

Given a string, find the first non-repeating character in it and return it’s index. If it doesn’t …