题解 | 找出字符串中第一个只出现一次的字符

第一次遍历：计数

第二次遍历：记录index并比较出最小值

s = input().strip()

alphabet = "zxcvbnmasdfghjklqwertyuiop"
counter_dict = {}

for each in alphabet:
    counter_dict[each] = s.count(each)
result_list = []
for each in counter_dict:
    if counter_dict[each] == 1:
        result_list.append(s.index(each))
if result_list:
    print(s[min(result_list)])
else:
    print(-1)