其他组数据都是3ms通过，不知道为什么第二组数据要用1.2s。代码如下。

#include <iostream>
using namespace std;
bool is_prime(int x){
	int  i = 2;
	bool flag = true;
	if (x <= 1) return false;
	while (i * i <= x){
		if (x % i == 0) {flag = false;break;}
	}
	return flag;
}
int main(){
	string s;
	cin >> s;
	int res[26];
	int n = s.size();
	for (int i = 0;i < 26;i++) {res[i] = 0;}
	for (int i = 0; i < n;i++){
	res[s[i] - 97] += 1;
	}
	int m1 = 1;int m2 = 100;
	for (int i = 0;i < 26;i++){
		if (res[i] > m1 ) {m1 = res[i];}
		if (res[i] < m2 && res[i] > 0) {m2 = res[i];}
	}
	if (is_prime(m1 - m2)){
		cout << "Lucky Word"  << endl << m1 - m2;
	}else cout << "No Answer" << endl << 0;
    return 0;
}

求大佬解答疑惑。