参考题解cpp

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <deque>
#include <unordered_map>
#include <map>
#include <cstring>
#include <cmath>
#include <unordered_set>
#include <set>
#include <utility>
#include <climits>
#include <iomanip>
#include <stack>
#include <bitset>

#define int long long
#define PII pair<int, int> 
#define TLLL tuple<int , int , int>
#define INF 0x3f3f3f3f3f3f3f3f
#define inf 0x3f
#define all(v) v.begin() + 1 , v.end()
#define ALL(v) v.begin() , v.end()
#define endl "\n"
#define i128 __int128_t
using namespace std;

bool isPrime(int n) 
{
    if (n <= 1) return false;
    if (n <= 3) return true;
    if (n % 2 == 0 || n % 3 == 0) return false;
    for (int i = 5; i * i <= n; i += 6) 
        if (n % i == 0 || n % (i + 2) == 0) return false;
    return true;
}

int reverse(int n) 
{
    int res = 0;
    while (n > 0) 
    {
        res = res * 10 + n % 10;
        n /= 10;
    }
    return res;
}

void solve()
{
    int count = 0;
    for (int i = 1; i <= 2025; i++) 
    {
        if (isPrime(i)) 
        {
            int rev = reverse(i);
            if (isPrime(rev)) 
                count ++;
        }
    }

    cout << count << endl;
    return ;
}

signed main() 
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int T = 1;
    // cin >> T;
    while (T -- ) solve();
    return 0;
}