Submission

Score: 90

User: ssens3

Problemset: จำนวนเฉพาะก่อนหน้า

Language: cpp

Time: 0.031 second

Submitted On: 2026-10-05 14:31:40

#include <iostream>
#include <vector>
using namespace std;
int main(){
    cin.tie(0)->sync_with_stdio(0);
    int n, c = 4, r[5] = {2,3,5,7,11}; cin >> n; vector<bool> p(n, 1); p[0] = 0; p[1] = 0;
    for (int i = 2; i * i <= n; i++){
        if (!p[i]) continue;
        for (int j = i * i; j <= n; j += i) p[j] = 0;
    }
    for (int i = n-1; i > 0; i--){
        if (p[i]){
            r[c] = i; c--;
        }
        if (c < 0) break; 
    }
    for (int i = 0; i < 5; i++) cout << r[i] << " ";

}