minimum-window-substring

class Solution {
public:
    string minWindow(string s, string t) {
        vector<int>mp(128,0);
        for(int i=0;i<t.size();i++)mp[t[i]]++;
        int counter=0,start=0,end=0,minstart=0,wind=INT_MAX;
        while(end<s.size())
        {
            if(mp[s[end]]>0)counter++;//必须写>0，不写是判断是否为0
            mp[s[end]]--;
            end++;
            while(counter==t.size())
            {
                if(wind>end-start)wind=end-start,minstart=start;
                mp[s[start]]++;
                if(mp[s[start]]>0)counter--;//必须写>0，不写是判断是否为0
                start++;
            }
        }
        return wind==INT_MAX?"":s.substr(minstart,wind);
    }
};