Java | Leetcode Java题解之第387题字符串中的第一个唯一字符
题目：
题解：
class Solution {
public int firstUniqChar(String s) {
Map<Character, Integer> position = new HashMap<Character, Integer>();
Queue<Pair> queue = new LinkedList<Pair>();
int n = s.length();
for (int i = 0; i < n; ++i) {
char ch = s.charAt(i);
if (!position.containsKey(ch)) {
position.put(ch, i);
queue.offer(new Pair(ch, i));
} else {
position.put(ch, -1);
while (!queue.isEmpty() && position.get(queue.peek().ch) == -1) {
queue.poll();
}
}
}
return queue.isEmpty() ? -1 : queue.poll().pos;
}
class Pair {
char ch;
int pos;
Pair(char ch, int pos) {
this.ch = ch;
this.pos = pos;
}
}
}