Submission

Score: 100

User: letdown

Problemset: จำนวนเฉพาะก่อนหน้า

Language: cpp

Time: 0.016 second

Submitted On: 2025-10-09 09:34:01

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;

    bool p[++n];
    memset(p+2, true, n*sizeof(bool));
    for (int i = 2; i*i <= n; i++) {
        if (p[i]) {
            for (int j = i*i; j <= n; j+=i) {
                p[j] = false;
            }
        }
    }
    
    int ans[5];
    int x = 4;
    for (int i = n - 2; i >= 0; i--) {
        if (x < 0) break;
        if (p[i]) {
            ans[x] = i;
            x--;
        }
    }
    for (auto a: ans) cout << a << " ";
}