题解 | #字符个数统计#

#include <stdio.h>

#define MAX_TABLE_SIZE 128
int main()
{
    char hash[MAX_TABLE_SIZE] = {-1};
    char c = 0;
    int num = 0;
    while(~scanf("%c", &c))
    {
        if (c == '\n')
            break;
        if (hash[(int)c] != c)
        {
            hash[(int)c] = c;
            num++;
        }
    }
    printf("%d\n", num);
    return 0;
}