双指针+滑动窗口

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        if(s.size() == 0) return 0;
        unordered_set<char> lookup;
        int maxStr = 0;
        int left = 0;
        for(int i = 0; i < s.size(); i++){
            while (lookup.find(s[i]) != lookup.end()){
                lookup.erase(s[left]);
                left ++;
            }
            maxStr = max(maxStr,i-left+1);
            lookup.insert(s[i]);
    }
        return maxStr;

    }
};

作者:powcai
链接:https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/solution/hua-dong-chuang-kou-by-powcai/
来源:力扣(LeetCode)
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