#include "highway.h"
#include<bits/stdc++.h>
#define vi vector<int>
#define vb vector<bool>
#define vpii vector<pair<int,int>>
#define pb push_back
#define vvi vector<vector<int>>
#define ll long long int
#define f0r(i,n) for(int i = 0; i<n; i++)
#define vout(v) for(auto u : v)cout<<u<<' '; cout<<'\n';
#define pii pair<int,int>
using namespace std;
ll base;
ll len;
int a;
int b;
int m;
pii search(int l, int r){
if(l == r)return{l, l};
vi w(m,0);
int mid = (l + r)/2;
for(int i = l; i<=mid; i++)w[i] = 1;
ll ret = ask(w);
if(ret == base){
return search(mid + 1, r);
}
else if(ret == len * b){
return search(l, mid);
}
else{
int cnt = (ret - base) / (b - a);
return {mid - cnt+1, mid - cnt + len};
}
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
m = U.size();
bool s3 = true;
f0r(i, m){
if(U[i] != i || V[i] != i+1)s3 = false;
}
a = A;
b = B;
ll ret;
vi w(m,0);
ret = ask(w);
base = ret;
len = ret/A;
if(s3){
pii ans = search(0, m-1);
answer(ans.first, ans.second + 1);
}
else{
vi dep(N);
dep[0] = 0;
queue<int>q;
q.push(0);
vb vis(N);
vis[0] = 1;
vpii adj[N];
f0r(i, m){
adj[U[i]].pb({V[i], i});
adj[V[i]].pb({U[i], i});
}
vi par(N, -1);
while(!q.empty()){
int cur = q.front();
q.pop();
for(auto u : adj[cur]){
if(vis[u.first])continue;
par[u.first] = u.second;
vis[u.first] = 1;
dep[u.first] = dep[cur] + 1;
q.push(u.first);
}
}
//vout(par);
vi poss;
f0r(i, N){
if(dep[i] == len)poss.pb(i);
}
//vout(poss);
int l = 0;
int r = poss.size() - 1;
while(l < r){
vi w(m, 0);
int mid = (l + r)/2;
//set l to mid
for(int i = l; i<=mid; i++){
w[par[poss[i]]] = 1;
}
ret = ask(w);
if(ret > base){
r = mid;
}
else{
l = mid + 1;
}
}
answer(0, poss[l]);
}
}
