题解 | #字符流中第一个不重复的字符#

public class Solution {
    //Insert one char from stringstream
    int[] zifu = new int[256];
    Queue<Character> q = new LinkedList<>();
    public void Insert(char ch)
    {
        if(zifu[ch] == 0){
            zifu[ch]++;
            q.offer(ch);
        }else{
            q.remove(ch);
        }
    }
  //return the first appearence once char in current stringstream
    public char FirstAppearingOnce()
    {
        if(q.isEmpty()){
            return '#';
        }else{
            return q.peek();
        }
    }
}