题解 | #找出字符串中第一个只出现一次的字符#
找出字符串中第一个只出现一次的字符
https://www.nowcoder.com/practice/e896d0f82f1246a3aa7b232ce38029d4
import sys str = sys.stdin.readline().strip() recorded = [] rep = set() for s in str: if s in recorded: recorded.remove(s) rep.add(s) if s not in recorded and s not in rep: recorded.append(s) if recorded != []: print(recorded[0]) else: print(-1)