Longest Substring Without Repeating Characters
来源:互联网 发布:人工智能 风口 编辑:程序博客网 时间:2024/05/16 05:47
1 问题描述
Given a string, find the length of the longest substring without repeating characters.
Examples:
Given “abcabcbb”, the answer is “abc”, which the length is 3.
Given “bbbbb”, the answer is “b”, with the length of 1.
Given “pwwkew”, the answer is “wke”, with the length of 3. Note that the answer must be a substring, “pwke” is a subsequence and not a substring.
2 求解思路
把某一个字符当做起始字符往后面开始访问。当访问到与起始字符相同的时候,则为由该开始字符所决定的最大非重复的子字符串。这种思路的算法复杂度为O(N*N),可以求得最长的子字符串。但是该题目仅仅要求我们求其最大长度。因此只需要维护起始位置即可。
3 实现代码
int lengthOfLongestSubstring(string s) { vector<int> dict(256,-1); int maxlen=0,start=-1; for(int i=0;i<s.length();++i){ if(dict[s[i]]>start) start=dict[s[i]]; dict[s[i]]=i; maxlen=max(maxlen,i-start); } return maxlen; }
比较trick的地方是start=dict[s[i]]这条语句,改变之前start表示了起始字符的前一个位置。如果起始位置为0,start 则为-1。当且仅当读到第一个与起始字符相同的字符是,条件才会成立,才会改变start的值。
0 0
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- Longest Substring Without Repeating Characters
- LeetCode 55. Jump Game and 45. Jump Game II 题解
- java_简陋租车系统
- (李兴华)【FANUC FOCAS1/2 Library 开发系列教程】-10分钟快速入门
- SURF SIFT ORB三种特征检测算法比较
- 机器学习之梯度下降法
- Longest Substring Without Repeating Characters
- Hibernate基础------》关系映射---》继承映射-》简单映射
- 100. Same Tree
- js实现操作剪贴板
- leetcode 389. Find the Difference
- 写了个鼠标键盘模拟器,希望对大家有用哈!
- ROS 学习系列 -- RViz 实时观测机器人建立导航2D封闭空间地图过程 (SLAM)
- Ardunio菜鸟教程(四)
- openlayers3应用(三):百度坐标“纠偏”