Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note:A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? confused what "{1,#,2,3}"
Given a string containing only digits, restore it by returning all possible valid IP address combinations. For example:Given "25525511135", return ["255.255.11.135", "255.255.111.35"]. (Order does not matter) 这道题要求是复原IP地址,IP地
Given a string containing only digits, restore it by returning all possible valid IP address combinations. Example: Input: "25525511135" Output: ["255.255.11.135", "255.255.111.35"] 给定一个只包含数字的字符串,复原它并返回所有可能的 IP 地址格式. 示例: 输入:
(不会,典型) 给定一个只包含数字的字符串,复原它并返回所有可能的 IP 地址格式. 示例: 输入: "25525511135" 输出: ["255.255.11.135", "255.255.111.35"] 1.回溯法+剪枝: public class Solution { public List<String> restoreIpAddresses(String s) { List<String> res = new
题目连接: Petr and Permutations 题意:给出一个1到n的序列,Petr打乱了3n次,Um_nik打乱了7n+1次,现在给出被打乱后的序列,求是谁打乱的. 题解:因为给出了一个3*n和一个7*n+1,发现这两个当一个为奇数另一个一定为偶数,所以可以联想和奇偶性质有关.但是这里面要算最短几步能把当前的序列变成1-n.这里我算错~~顺便学了一下如何将置换序列复原. #include<bits/stdc++.h> using namespace std; typedef pair
1555: Inversion Sequence Submit Page Summary Time Limit: 2 Sec Memory Limit: 256 Mb Submitted: 519 Solved: 195 Description For sequence i1, i2, i3, … , iN, we set aj to be the number of members in the sequence which are prior to j a