题解 | 字符流中第一个不重复的字符

#include <unordered_map>
class Solution
{
public:
  //Insert one char from stringstream
    queue<char> q;
    unordered_map<char,int >ump;
    void Insert(char ch) {
         q.push(ch);
         ump[ch]+=1;
    }
  // return the first appearence once char in current stringstream
    char FirstAppearingOnce() {
       while(ump[q.front()]!=1)
       {
        q.pop();
        if(q.empty())
        {
            return '#';
        }
       }
       return q.front();
        
    }

};