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Submission #1048821

# Submission time Handle Problem Language Result Execution time Memory
1048821 2024-08-08T09:39:46 Z Whisper Easter Eggs (info1cup17_eastereggs) C++17
100 / 100
 15 ms 736 KB 
#include <bits/stdc++.h>
#include "grader.h"

using namespace std;
using ll = long long;

int findEgg (int _N, vector<pair<int, int>> bridges){
    int N = _N;
    vector<vector<int>> G(N + 5);
    for (pair<int, int>&x : bridges){
        int u = x.first, v = x.second;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    vector<int> minDist(N + 5), rev(N + 5);
    queue<int> q;
    q.emplace(1);
    minDist[1] = 1; rev[1] = 1;
    int cnt = 1;
    while(q.size()){
        int u = q.front(); q.pop();
        for (int &v : G[u]){
            if (!minDist[v]){
                q.emplace(v);
                minDist[v] = ++cnt;
                rev[minDist[v]] = v;
            }
        }
    }
    auto check = [&](int x) -> bool{
        vector<int> node;
        for (int i = 1; i <= N; ++i) if(minDist[i] <= x){
            node.emplace_back(i);
        }
        return query(node);
    };
    int l = 1, r = N;
    while (l < r){
        int m = (l + r) >> 1;
        if(check(m)) r = m;
        else l = m + 1;
    }
    return rev[l];
}

Subtask #1
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Number of queries: 4
2 Correct 1 ms 424 KB Number of queries: 4
3 Correct 0 ms 344 KB Number of queries: 4
4 Correct 0 ms 344 KB Number of queries: 4

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 464 KB Number of queries: 8
2 Correct 6 ms 492 KB Number of queries: 9
3 Correct 15 ms 488 KB Number of queries: 9
4 Correct 8 ms 492 KB Number of queries: 9

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 344 KB Number of queries: 9
2 Correct 8 ms 500 KB Number of queries: 9
3 Correct 8 ms 736 KB Number of queries: 9
4 Correct 13 ms 496 KB Number of queries: 9