Submission #1099668

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099668		tuannm	Easter Eggs (info1cup17_eastereggs)	C++17	0 / 100	1 ms	600 KiB

eastereggs

#include<bits/stdc++.h>
#include "grader.h"
#define ii pair<int, int>
#define fi first
#define se second
#define pb push_back
using namespace std;
const int maxN = 520;

bool removed[maxN];
int sz[maxN], in[maxN], out[maxN], cnt;
vector<int> adj[maxN];

/*
bool isEgg[maxN];

bool query(vector<int> gg){
    for(int i : gg)
        if(isEgg[i])
            return true;

    return false;
}
*/

void DFS(int u = 1, int p = 0){
    in[u] = ++cnt;
    sz[u] = 1;

    for(int v : adj[u]){
        if(removed[v] || v == p)
            continue;

        DFS(v, u);
        sz[u] += sz[v];
    }

    out[u] = cnt;
}

int findEgg(int N, vector<ii> bridges){
    for(auto [u, v] : bridges)
        adj[u].pb(v), adj[v].pb(u);

    for(int Q = 1; Q <= 60; ++Q){
        cnt = 0;

        int root = 0;

        for(int i = 1; i <= N; ++i){
            if(removed[i])
                continue;

            root = i;
            break;
        }

        DFS(root);

        int zz = sz[root] / 2;
        int s = root;
        for(int i = 1; i <= N; ++i){
            if(removed[i])
                continue;

            if(abs(zz - sz[i]) < abs(zz - sz[s]))
                s = i;
        }

        vector<int> vec;

        for(int i = 1; i <= N; ++i){
            if(removed[i])
                continue;

            if(in[s] <= in[i] && in[i] <= out[s])
                vec.pb(i);
        }

        if(query(vec)){
            for(int i = 1; i <= N; ++i){
                if(removed[i])
                    continue;

                if(in[s] <= in[i] && in[i] <= out[s])
                    continue;

                removed[i] = true;
            }
        }
        else{
            for(int i : vec)
                removed[i] = true;
        }

        int cntRem = 0;

        for(int i = 1; i <= N; ++i)
            cntRem += !removed[i];

        if(cntRem == 1){
            for(int i = 1; i <= N; ++i)
                if(!removed[i])
                    return i;
        }
    }
    return -1;
}

/*
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());

int Rand(int l, int r){
    return l + rd() % (r - l + 1);
}

int main(){
    for(int __ = 1; __ <= 100; ++__){
        int N = Rand(512, 512);

        vector<ii> bridges;

        for(int i = 2; i <= N; ++i)
            bridges.pb({i, Rand(1, i - 1)});

        for(int i = 1; i <= N; ++i)
            isEgg[i] = Rand(0, 1);

        int gg = Rand(1, N);
        isEgg[gg] = true;

        int u = findEgg(N, bridges);

        for(int i = 1; i <= N; ++i)
            removed[i] = false, adj[i].clear();

        if(!isEgg[u]){
            cout << "Wrong on test " << __ << ":\n";
            cout << N << "\n";
            for(auto [x, y] : bridges)
                cout << x << " " << y << "\n";

            for(int i = 1; i <= N; ++i)
                if(isEgg[i])
                    cout << i << " ";

            cout << "\nYour answer: " << u << ".\n";
            return 0;
        }

        for(int i = 1; i <= N; ++i)
            isEgg[i] = false;
    }

    cout << "OK.\n";
}
*/

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