题解 | #素数回文#

知识点：

函数：函数

#include <iostream>
#include <algorithm>
using namespace std;

bool isPrime(long n);

int main() {
    string t;
    cin >> t;
    string b = t;
    long n;

    reverse(t.begin(), t.end());
    t.erase(t.begin());
    b += t;
    n = atol(b.c_str());

    if (isPrime(n)) {
        cout << "prime";
    } else {
        cout << "noprime";
    }

    return 0;
}

bool isPrime(long n) {
    bool ret = true;

    for (long i = 2; i * i < n; i++) {
        if (n % i == 0) {
            ret = false;
            break;
        }
    }

    return ret;
}

/*
long fun(int n);

bool isPrime(long n);

int main() {
    int t;
    cin >> t;
    long temp;

    temp = fun(t);

    if (isPrime(temp)) {
        cout << "prime";
    } else {
        cout << "noprime";
    }

    return 0;
}

long fun(int n) {
    int ret;
    long t = n;
    int temp;

    n /= 10;

    while (n) {
        t = t * 10 + n % 10;
        n /= 10;
    }

    return t;
}

bool isPrime(long n) {
    bool ret = true;

    for (long i = 2; i*i < n; i++) {
        if (n % i == 0) {
            ret = false;
            break;
        }
    }

    return ret;
}
*/