题解 | #图片整理#

int main(void)
{
    char str[1001][1] = {'\0'};
    int hash[1001] = {0};
    char ch;
    int i = 0;
    
    while ((ch = getchar()) != '\n')
    {
        int tmp = ch;
        if (str[tmp][1] != '\0')
            hash[tmp]++;
        else
        {
            str[tmp][1] = ch;
            hash[tmp] = 1;
        }
    }
    
    for (int j = 0; j < 1001; ++j)
    {
        while (hash[j] > 0)
        {
            printf("%c", str[j][1]);
            hash[j]--;
        }
    }
    return 0;
}