没有重复字符的最长子串

从现在开始，努力学习吧！本文《没有重复字符的最长子串》主要讲解了等等相关知识点，我会在golang学习网中持续更新相关的系列文章，欢迎大家关注并积极留言建议。下面就先一起来看一下本篇正文内容吧，希望能帮到你！

问题

暴力方法将涉及创建给定字符串的所有可能的子字符串，并找出哪个是最长的没有重复字符的子字符串。这将导致 tc:o(n^2)

最佳方法：
tc：o(n)
sc : o(256)，用于使用大小为 256 的 int[]

class Solution {
    public int lengthOfLongestSubstring(String s) {
        int hash[] = new int[256];// size of all the ascii characters
        Arrays.fill(hash,-1); // -1 to indicate these indexes don't have any character visited already
        int left =0,right =0;
        int max = 0;
        while(right<s.length()){
            char  c = s.charAt(right);
            if(hash[c]!=-1){// means the character has been seen in the past
                if(hash[c]>=left){// if the index of the character seen in the past is after the left pointer, then left pointer should be updated, to avoid duplicate in the window of substring
                    left  = hash[c] + 1;// has to be 1 index after the index of last seen duplicate character
                }
            }
            max = Integer.max(max, right-left+1);// keep track of mas window substring
            hash[c]  = right;// update the character last seen index in hash
            right++;
        }
        return max;
    }
}

终于介绍完啦！小伙伴们，这篇关于《没有重复字符的最长子串》的介绍应该让你收获多多了吧！欢迎大家收藏或分享给更多需要学习的朋友吧~golang学习网公众号也会发布文章相关知识，快来关注吧！