C++/代码/hashmap

C++/代码/Hashmap

class Solution
{
public:
  //Insert one char from stringstream
    unordered_map<char,int> mmap;
    string s;
    void Insert(char ch) {
        s += ch;
        mmap[ch]++;
    }
  //return the first appearence once char in current stringstream
    char FirstAppearingOnce() {
        for (char c : s) if (mmap[c] == 1) return c;
        return '#';
    }

};