#include "highway.h"
#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using ii = pair<int, int>;
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
int M = U.size();
vector<vector<ii> > adj(N);
for (int i = 0; i < M; i++) {
adj[U[i]].emplace_back(V[i], i);
adj[V[i]].emplace_back(U[i], i);
}
int64_t all_b = ask(vector<int>(M, 1)),
all_a = all_b / B * A;
int lo = -1, hi = M-1;
while (hi - lo > 1) {
int mid = (lo + hi) >> 1;
vector<int> orz(M, 0);
for (int i = 0; i <= mid; i++) orz[i] = 1;
if (ask(orz) == all_b) hi = mid;
else lo = mid;
}
int X = U[hi], Y = V[hi], S, T;
vector<int> depthX(N, INT_MAX), depthY(N, INT_MAX);
if (1) {
queue<int> q;
q.push(X); depthX[X] = 0;
while (!q.empty()) {
int u = q.front(); q.pop();
for (auto [v, idx] : adj[u])
if (depthX[v] == INT_MAX) {
depthX[v] = depthX[u] + 1;
q.push(v);
}
}
}
if (1) {
queue<int> q;
q.push(Y); depthY[Y] = 0;
while (!q.empty()) {
int u = q.front(); q.pop();
for (auto [v, idx] : adj[u])
if (depthY[v] == INT_MAX) {
depthY[v] = depthY[u] + 1;
q.push(v);
}
}
}
vector<int> lisX, lisY;
for (int i = 0; i < N; i++)
if (depthX[i] != depthY[i]) {
if (depthX[i] < depthY[i]) lisX.emplace_back(i);
else lisY.emplace_back(i);
}
sort(lisX.begin(), lisX.end(), [&](int x, int y) {return depthX[x] > depthX[y];});
sort(lisY.begin(), lisY.end(), [&](int x, int y) {return depthX[x] > depthX[y];});
if (1) {
int lo = -1, hi = lisX.size()-1;
while (hi - lo > 1) {
int mid = (lo + hi) >> 1;
vector<int> orz(M, 0);
for (int i = 0; i <= mid; i++) for (auto [v, idx] : adj[lisX[i]]) orz[idx] = 1;
if (ask(orz) != all_a) hi = mid;
else lo = mid;
}
S = lisX[hi];
}
if (1) {
int lo = -1, hi = lisY.size()-1;
while (hi - lo > 1) {
int mid = (lo + hi) >> 1;
vector<int> orz(M, 0);
for (int i = 0; i <= mid; i++) for (auto [v, idx] : adj[lisY[i]]) orz[idx] = 1;
if (ask(orz) != all_a) hi = mid;
else lo = mid;
}
T = lisY[hi];
}
answer(S, T);
}
/*
4 3
1 3 1 3
1 2
2 0
0 3
*/
