#include <bits/stdc++.h>
//#include "grader.h"
#define X first
#define Y second
using namespace std;
vector<int> g[1010];
vector<int> half;
vector<int> all;
vector<int> help;
vector<int> dod;
int have;
bool took[1010];
bool nxt[1010];
bool need[1010];
/*
int egg;
bool query(vector< int > v){
for(int x : v)
if(x == egg)
return true;
return false;
}
*/
bool dfs(int x, int last){
bool out = need[x];
for(int y : g[x]){
if(y == last) continue;
out |= dfs(y, x);
}
if(out) all.push_back(x);
return out;
}
void fix(){
dod.clear();
memset(need, 0, sizeof(need));
for(int x : all)
need[x] = true;
int start = all[0];
all.clear();
dfs(start, -1);
for(int x : dod)
all.push_back(x);
}
void findHalf(int x, int par){
if(have == 0)
return;
if(took[x]){
nxt[x] = true;
half.push_back(x);
have--;
}
for(int y : g[x]){
if(y == par)
continue;
findHalf(y, x);
}
}
int findEgg (int N, vector< pair< int, int > > graf ){
for(int i = 0; i < 1010; i++)
g[i].clear();
for(int i = 0; i < N - 1; i++){
int x = graf[i].X;
int y = graf[i].Y;
g[x].push_back(y);
g[y].push_back(x);
if(!took[x]){
all.push_back(x);
took[x] = true;
}
if(!took[y]){
all.push_back(y);
took[y] = true;
}
}
int ret = -1;
while(all.size() > 1){
//for(int x : all) cout << x << " ";
fix();
//cout << "\n";
//for(int x : all) cout << x << " ";
//cout << "\n";
have = N / 2;
half.clear();
memset(nxt, false, sizeof(nxt));
findHalf(all[0], -1);
//for(int x : half) cout << x << " half \n";
int ans = query(half);
//cout << ans << " ans to the query\n";
if(ans == 1){
N /= 2;
}
else{
if(ans == -1){
all.clear();
break;
}
N = N - N / 2;
}
help.clear();
for(int x : all){
if(took[x] and nxt[x] == ans)
help.push_back(x);
else
took[x] = false;
}
all.clear();
for(int x : help){
//cout << x << " took to the nxt query\n";
all.push_back(x);
}
}
if(all.size())
ret = all[0];
memset(took, 0, sizeof(took));
all.clear();
half.clear();
help.clear();
dod.clear();
have = 0;
return ret;
}
/*
int main(){
for(int j = 0; j < 3; j++){
int m;
cout << "num. of nodes\n";
cin >> m;
cout << "easter egg\n";
cin >> egg;
vector< pair<int, int> > inp;
for(int i = 0; i < m - 1; i++){
int a, b;
cin >> a >> b;
inp.push_back({a, b});
}
cout << findEgg(m, inp);
}
return 0;
} */
Compilation message
eastereggs.cpp: In function 'int findEgg(int, std::vector<std::pair<int, int> >)':
eastereggs.cpp:124:13: error: 'query' was not declared in this scope
124 | int ans = query(half);
| ^~~~~
