我是直接设定max少一个，也就是maxn-minn

#include <stdio.h>
#include <math.h>

int isPrime(int num)
{
	if (num <= 1)
	{
		return 0;
	}
	for (int i = 2; i <= (int) sqrt ((double)num); i++)
	{
		if (num % i == 0)
		{
			return 0;
		}
	}
	return 1;
}
int main()
{
	char str[100];
	scanf("%s", str);
	int count[256] = { 0 };
	for (int i = 0; str[i] != '\0'; i++)
	{
		for (int j = i+1; str[j] != '\0'; j++)
		{
			if (str[i] == str[j])
			{
				count[i]++;
			}
		}
	}
	int max = count[0];
	for (int i = 0; i < 256; i++)
	{
		if (count[i]>max)
			max = count[i];
	}
	if (isPrime(max))
	{
		printf("Lucky Word\n");
		printf("%d\n", max);
	}
	else
	{
		printf("No Answer\n");
		printf("0\n");
	}
	
	return 0;
}