题解 | #找出字符串中第一个只出现一次的字符#

Python hashmap统计字母出现次数

while True:
    try:
        input_str = input()
        num_dict = {}
        res = ''
        for i in range(len(input_str)):
            if input_str[i] in num_dict:
                num_dict[input_str[i]] += 1
            else:
                num_dict[input_str[i]] = 1
        for j in input_str:
            if num_dict[j] == 1:
                res = j
                break
        if res != '':
            print(res)
        else:
            print(-1)
    except:
        break