제출 #1173188

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1173188		nguyenkhangninh99	Easter Eggs (info1cup17_eastereggs)	C++17	0 / 100	6 ms	7488 KiB

eastereggs

#include "grader.h"
#include <bits/stdc++.h>

using namespace std;

const int maxn = 2e5 + 5;
int tin[maxn], f[maxn], timeDfs;
vector<int> g[maxn];

void dfs(int u, int pre){
    tin[u] = ++timeDfs;
    f[timeDfs] = u;

    for(int v: g[u]){
        if(v != pre) dfs(v, u);
    }
}

/*int query(vector<int> x){
    for(int v: x) cout << v << " ";
    cout << '\n';
    int k; cin >> k;
    return k;
}
*/
int findEgg(int N, vector <pair<int, int>> bridges){
    int n = N;

    for(int i = 0; i < n - 1; i++){
        int u = bridges[i].first, v = bridges[i].second;
        g[u].push_back(v);
        g[v].push_back(u);
    }

    dfs(1, 0);

    int l = 1, r = n, ans = -1;

    while(l <= r){
        int mid = (l + r) / 2;
        
        vector<int> v;
        for(int i = 1; i <= mid; i++) v.push_back(f[i]);
    
        if(query(v) == 1){
            ans = mid;
            r = mid - 1;
        }
        else l = mid + 1;
    }

    return f[ans];
}

/*signed main(){
    int n = 5;
    vector<pair<int, int>> k;
    k.push_back({1, 2});
    k.push_back({1, 3});
    k.push_back({2, 4});
    k.push_back({4, 5});
    cout << findEgg(n, k);
}*/

• Subtask 1: 0 / 40
• Subtask 2: 0 / 40
• Subtask 3: 0 / 20