백준 2960번 C++

#include <iostream>

#include <algorithm>

using namespace std;

const int MAX = 1003;

int n, k;

int arr[MAX];

int main(void) {

cin >> n >> k;

for (int i = 2; i <= n; i++) {

arr[i] = i;

}

int counts = 0;

for (int i = 2; i <= n; i++) {

for (int j = 1; i*j <= n; j++) {

if (arr[i*j] == -1)

continue;

arr[i*j] = -1;

counts++;

if (counts == k) {

cout << i * j;

return 0;

}

}

}

return 0;

}