3. 无重复字符的最长子串

leetcode-3. 无重复字符的最长子串

这道题最主要的考察点还是滑动窗口，但是刚刚学习了C++中的哈希表用法，练习一下api调用。

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        int fastIndex = 0, slowIndex = 0, size = 0;
        int maxSize = 0;
        unordered_set<char> words;
        while(fastIndex < s.size())
        {
            if(words.count(s[fastIndex]) == 0)
            {
                words.insert(s[fastIndex]);
                fastIndex++;
                size++;
                if(size > maxSize)
                maxSize++;
            }
            else
            {
                while(words.count(s[fastIndex]) != 0)
                {
                    words.erase(s[slowIndex]);
                    slowIndex++;
                    size--;
                }
            }
        }
        return maxSize;
    }
};