yaxi_wx的专栏

Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".这里有两种qing

Sort a linked list using insertion sort./** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { *         val = x;

Given an array of integers, every element appears twice except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using e

Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical and the nodes have the same value.采用先序遍历的思想，

Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.比较左右子树的高度，选最高的叠加

Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?

Given n, how many structurally unique BST's (binary search trees) that store values 1...n?For example,Given n = 3, there are a total of 5 unique BST's.当n = 0 时为空树，所以BST的个数为1当n = 1 时只有一个节点，

Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321