JZ54-字符流中第一个不重复的字符
字符流中第一个不重复的字符
https://www.nowcoder.com/practice/00de97733b8e4f97a3fb5c680ee10720?tpId=13&tags=&title=&diffculty=0&judgeStatus=0&rp=1&tab=answerKey
class Solution {
private int[] cnts = new int[256];
private Queue<Character> queue = new LinkedList<>();
public void Insert(char ch) {
cnts[ch]++;
queue.add(ch);
while (!queue.isEmpty() && cnts[queue.peek()] > 1) {
queue.poll(); //把队列首部，但是重复的字符全弹出,只保留无重复的数字。g go goo-> g g -> null l e --> l e
}
}
public char FirstAppearingOnce() {
return queue.isEmpty() ? '#' : queue.peek(); //弹出 l
}
} 