백준 6359번 C++

#include <iostream>

#include <cstring>

using namespace std;

const int MAX = 101;

int t,room;

int roomnum[MAX];

int escape(int r) {

memset(roomnum, 0, sizeof(roomnum));

for (int i = 1; i <= r; i++) {

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

if (roomnum[i*j] == 0)

roomnum[i*j] = 1;

else

roomnum[i*j] = 0;

}

}

int answer = 0;

for (int i = 1; i <= r; i++) {

if (roomnum[i] == 1)

answer++;

}

return answer;

}

int main(void) {

cin >> t;

for (int i = 0; i < t; i++) {

cin >> room;

cout << escape(room) << endl;

}

return 0;

}