Submission #1840741

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int N, M;
vector<vector<int>> roads;
vector<bool> if_friend_of_friend;
vector<bool> if_friend;

void friend_of_friend(int now, int friend_count){
    if(friend_count == 2){
        if_friend_of_friend[now] = true;
    }else{
        if_friend[now] = true;
        for(int i = 0; i < roads[now].size(); i++){
            friend_of_friend(roads[now][i], friend_count + 1);
        }
    }
}

int main(){
    cin >> N >> M;
    roads.resize(N);
    for(int i = 0; i < M; i++){
        int left, right;
        cin >> left >> right;
        roads[left - 1].push_back(right - 1);
        roads[right - 1].push_back(left - 1);
    }
    if_friend.resize(N);
    if_friend_of_friend.resize(N);
    for(int i = 0; i < N; i++){
        fill(if_friend.begin(), if_friend.end(), false);
        fill(if_friend_of_friend.begin(), if_friend_of_friend.end(), false);
        friend_of_friend(i, 0);
        int ans = 0;
        for(int j = 0; j < N; j++){
            if(!if_friend[j] && if_friend_of_friend[j]){
                ans++;
            }
        }
        cout << ans << endl;
    }
}

Submission Info

Judge Result