Longest Substring Without Repeating Characters

最新推荐文章于 2025-05-18 01:04:12 发布

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最新推荐文章于 2025-05-18 01:04:12 发布

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本文链接：https://blog.youkuaiyun.com/nutcc/article/details/10418401

本文介绍了一种求解字符串中最长无重复字符子串长度的方法，并提供了一个Java实现示例。通过使用滑动窗口技术和哈希表来记录字符位置，有效解决了该问题。

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Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. For "bbbbb" the longest substring is "b", with the length of 1.

public class Solution {
    public int lengthOfLongestSubstring(String s) {
    
        if(s==null||s.length()==0) return 0;
        if(s.length()==1) return 1;
        
        char[] c = s.toCharArray();
        
        int longest = 0,index = 0,now = 0;
        int [] map = new int[26];
        Arrays.fill(map,-1);  //下标有可能会出现 0！！ 所以不可以用0！！
        for(int i=0;i<c.length;i++){
            if(map[c[i]-'a']==-1||map[c[i]-'a']<index){  //后者剔除一些错误的存留数据！！
                now++;
                map[c[i]-'a']=i;
                if(now>longest){
                    longest = now;
                }
            }else{
                now-=(map[c[i]-'a']-index);
                index = map[c[i]-'a']+1;
                map[c[i]-'a'] = i;
            }
        }
        return longest;
    }
}