题解 | #字符流中第一个不重复的字符#

#include <unordered_map>
class Solution {
 public:
  queue<char> qu;
  unordered_map<char, int> umap;
  //Insert one char from stringstream
  void Insert(char ch) {
    if (umap.find(ch) == umap.end()) {
      umap.insert({ch, 1});
      qu.push(ch);
    } else {
      umap[ch]++;
    }
  }
  //return the first appearence once char in current stringstream
  char FirstAppearingOnce() {
    int i = 0;
    int qsize = qu.size();
    while (i < qsize) {
      char front_value = qu.front();
      if (umap[front_value] != 1) {
        qu.pop();
        i++;
        continue;
      } else {
        return front_value;
      }
      i++;
    }
    return '#';
  }

};