u_s_er_na_me @ 2023-08-23 19:11:33
#include <iostream>
using namespace std;
int reverse(int j)
{
int sum = 0;
while (j != 0)
{
sum = sum * 10 + j % 10;
j /= 10;
}
return sum;
}
bool check(int a)
{
for (int i = 2;i * i <= a;i++)
{
if (a % i == 0) return 0;
}
return 1;
}
int main()
{
int a,b;
cin >> a >> b;
for (int i = a;i <= b;i++)
{
if (i == reverse(i) && check(i))
cout << i << endl;
}
}
by Igallta @ 2023-08-23 20:20:18
先判断是否是2的倍数以及是否是 2 会快很多。