백준 1325번 C++ 풀이

최적화를 안 해서 메모리와 시간사용량이 대단합니다.

#include <iostream>
#include <algorithm>
#include <queue>
#include <climits>
using namespace std;
vector <int> buffer[10001];
bool isVisited[10001];
int maxHackable[10001];
int main(){
    cin.tie(NULL);
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    for (auto i=0; i<m; i++){
        int a, b;
        cin >> a >> b;
        // a가 b를 신뢰한다 -> b 해킹시 a
        buffer[b].push_back(a);
    }
    priority_queue<pair<int, int>> pq;
    for (auto i=1; i<=n; i++){
        for (auto j=1; j<=n; j++){
            isVisited[j] = false;
        }
        queue<int> q;
        isVisited[i] = true;
        q.push(i);
        while (!q.empty()){
            int size = q.size();
            for (auto j=0; j<size; j++){
                int top = q.front();
                q.pop();
                for ( int next : buffer[top]){
                    if (!isVisited[next]){
                        isVisited[next] = true;
                        q.push(next);
                    }
                }
            }

        }
        int hacked = 0;
        for (auto i=1; i<=n; i++){
            if (isVisited[i]) hacked++;
        }
        maxHackable[i] = hacked;
    }
    int maxHackableNumeber = *max_element(maxHackable+1, maxHackable+n+1);
    for (auto i=1; i<=n; i++){
        if (maxHackableNumeber == maxHackable[i]){
            cout << i << ' ';
        }
    }
    return 0;

}