C++, time: O(n^2) space: O(0) class Solution { public: /** * @param str: a string * @return: a boolean */ bool isUnique(string &str) { // write your code here ; i<str.size(); i++) { ; j<str.size(); j++) { if (str[i] == str[j]) { return false; }…

Description Implement an algorithm to determine if a string has all unique characters. Example Given "abc", return true. Given "aab", return false. Challenge What if you can not use additional data structures? 解题:题目要求判断字符串是否有重复的元素,并且要求…

1.1 Implement an algorithm to determine if a string has all unique characters. What if you cannot use additional data structure? 这道题让我们判断一个字符串中是否有重复的字符,要求不用特殊的数据结构,这里应该是指哈希表之类的不让用.像普通的整型数组应该还是能用的,这道题的小技巧就是用整型数组来代替哈希表,在之前Bitwise AND of Numbers Range 数…

原题链接在这里:https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/ 题目: Given an array of strings arr. String s is a concatenation of a sub-sequence of arr which have unique characters. Return the maximum possible le…

题目如下: Given an array of strings arr. String s is a concatenation of a sub-sequence of arr which have unique characters. Return the maximum possible length of s. Example 1: Input: arr = ["un","iq","ue"] Output: 4 Explanation:…

题目: 判断字符串是否没有重复字符 实现一个算法确定字符串中的字符是否均唯一出现 样例 给出"abc",返回 true 给出"aab",返回 false 挑战 如果不使用额外的存储空间,你的算法该如何改变? 解题: 定义一个集合最简单. Java程序: public class Solution { /** * @param str: a string * @return: a boolean */ public boolean isUnique(String st…

C++ dp 递推式:dp[i][j] = dp[i-1][j] + dp[i][j-1] 初值:dp[i][j] = 1,i=0 or j=0 空间优化:省掉一维 class Solution { public: /** * @param n, m: positive integer (1 <= n ,m <= 100) * @return an integer */ int uniquePaths(int m, int n) { // wirte your code here vector…

Yet Another Source Code for LintCode Current Status : 232AC / 289ALL in Language C++, Up to date (2016-02-10) For more problems and solutions, you can see my LintCode repository. I'll keep updating for full summary and better solutions. See cnblogs t…

Given a string, find the longest substring that contains only two unique characters. For example, given "abcbbbbcccbdddadacb", the longest substring that contains k unique character is "bcbbbbcccb". 分析: 用hashmap记录每个character从start到当前位置…

A character is unique in string S if it occurs exactly once in it. For example, in string S = "LETTER", the only unique characters are "L" and "R". Let's define UNIQ(S) as the number of unique characters in string S. For exam…