#include "highway.h"
#include <vector>
#include <queue>
#include <utility>
#include <iostream>
#define MAXN 90005
#define MAXE 130005
using namespace std;
queue <int> Q;
vector <pair<int,int> > adj[MAXN];
bool color[MAXN], vis[MAXN], inTree[MAXE];
int eid[MAXN];
vector <int> dist[2]; //ordered by dist
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
int M = U.size();
vector<int> w(M);
for (int i = 0; i < M; ++i) {
w[i] = 0;
}
long long base = ask(w);
int lo = -1, hi = M-1; //find edge on shortest path
while (lo + 1 != hi) {
int mid = (lo + hi) >> 1;
for (int i=0; i < M; i++) {
w[i] = i <= mid;
}
if (ask(w) != base) {hi = mid;}
else {lo = mid;}
}
Q.push(U[hi]);
Q.push(V[hi]);
color[V[hi]] = true;
inTree[hi] = true;
vis[U[hi]] = vis[V[hi]] = true;
for (int i=0; i<M; i++) {
adj[U[i]].push_back({V[i], i});
adj[V[i]].push_back({U[i], i});
}
while (Q.size()) {
int u = Q.front();
Q.pop();
dist[color[u]].push_back(u);
for (auto v: adj[u]) {
if (vis[v.first]) {continue;}
vis[v.first] = true;
inTree[v.second] = true;
eid[v.first] = v.second;
color[v.first] = color[u];
Q.push(v.first);
}
}
lo = 0, hi = dist[0].size()-1;
while (lo != hi) {
int mid = (lo + hi + 1) >> 1;
for (int i=0; i<M; i++) {
w[i] = !inTree[i];
}
for (int i=dist[0].size()-1; i>=mid; i--) {
w[eid[dist[0][i]]]=1;
}
if (ask(w) == base) {hi = mid-1;}
else {lo = mid;}
}
int retA = dist[0][lo];
lo = 0, hi = dist[1].size()-1;
while (lo != hi) {
int mid = (lo + hi + 1) >> 1;
for (int i=0; i<M; i++) {
w[i] = !inTree[i];
}
for (int i=dist[1].size()-1; i>=mid; i--) {
w[eid[dist[1][i]]]=1;
}
if (ask(w) == base) {hi = mid-1;}
else {lo = mid;}
}
int retB = dist[1][lo];
answer(retA, retB);
}
