Submission #269752

#	Time	Username	Problem	Language	Result	Execution time	Memory
269752		theStaticMind	Easter Eggs (info1cup17_eastereggs)	C++14	71.60 / 100	15 ms	384 KiB

eastereggs

#include<bits/stdc++.h>
#define pb push_back
#define ii pair<int,int>
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define INF 100000000000000000
#define modulo 1000000007
#define mod 998244353
using namespace std;

#include "grader.h"

vector<int> adj[1000];
vector<int> sub(1000);
vector<bool> let(1000, false);

void dfs(int x, int pre){
    sub[x] = 1;
    for(auto y : adj[x]){
        if(y == pre || !let[y]) continue;
        dfs(y, x);
        sub[x] += sub[y];
    }
}

int find_centroid(int x, int pre, int sum){
    for(auto y : adj[x]){
        if(y == pre || !let[y]) continue;
        if(sub[y] > sum / 2) return find_centroid(y, x, sum);
    }
    return x;
}

void addall(int x, int pre, vector<int>& A){
    A.pb(x);
    for(auto y : adj[x]){
        if(y == pre || !let[y]) continue;
        addall(y, x, A);
    }
}

void split(int x, int pre, int s, vector<int>&L,vector<int>&R){
    L.pb(x);
    R.pb(x);
    s--;
    for(auto y : adj[x]){
        if(y == pre || !let[y]) continue;
        if(s >= sub[y]){
            addall(y, x, L);
            s -= sub[y];
        }
        else {
            addall(y, x, R);
        }
    }
}

int queryall(vector<int>& arr){
    for(int i = 0; i < sz(arr) - 1; i++){
        int x = arr[i];
        if(query({x})) return x;
    }
    return arr.back();
}

int solve(vector<int> comp){
    for(auto x : comp) let[x] = true;
    
    if(comp.empty()) assert(0);
    
    dfs(comp[0], -1);
    int root = find_centroid(comp[0], -1, sub[comp[0]]);
    dfs(root, -1);
    
    if(sz(comp) <= 3) return queryall(comp);

    vector<int> left, right;
  

    split(root, -1, (sub[root] - 1) / 2 + 1, left, right);

    for(auto x : comp) let[x] = false;
    
  if(right.size() == 1){
        return queryall(left);
    }
    if(left.size() == 1){
        return queryall(right);
    }
    if(query(left)){
        return solve(left);     
    }
    else {
        return solve(right);        
    }
}

void init(vector < pair < int, int > >& bridges){
    static bool yes = true;
    if(yes)
    for(auto p : bridges){
        adj[p.first].pb(p.second);
        adj[p.second].pb(p.first);
    }
    yes = false;
}

int findEgg (int N, vector < pair < int, int > > bridges)
{   
    init(bridges);
    vector<int> arr;
    for(int i = 1; i <= N; i++) arr.pb(i), let[i] = false;
    return solve(arr);
}

• Subtask 1: 32 / 40
• Subtask 2: 26.4 / 40
• Subtask 3: 13.2 / 20