# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1099666 | tuannm | Easter Eggs (info1cup17_eastereggs) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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";
}
*/