#include "migrations.h"
#include <bits/stdc++.h>
using namespace std;
int n;
int P[10000];
vector<int> g[10000];
int dist[10000] = {0};
void dfs(int u, int p = -1)
{
if (p == -1) dist[u] = 0;
for (int v : g[u]) if (v != p) {
dist[v] = dist[u] + 1;
dfs(v, u);
}
}
int prev_a, prev_b;
int a, b;
void find_diameter()
{
prev_a = a;
prev_b = b;
a = b = 0;
dfs(0);
for (int i = 0; i < n; i++)
if (dist[i] > dist[a])
a = i;
dfs(a);
for (int i = 0; i < n; i++)
if (dist[i] > dist[b])
b = i;
// make sure the one that remained the same is in the same position.
if (prev_b == a)
swap(a, b);
if (prev_a == b)
swap(a, b);
}
// can both change at once?
// can it go from (u,v) -> (x,y) where none of u,v,x,y are equal?
// well then surely the intermediate step (u,x) or (v,x) must have been answer?
bool cancelled = false;
int send_message(int N, int i, int Pi)
{
n = N;
g[i].push_back(Pi);
g[Pi].push_back(i);
if (N - 28 <= i && i < N - 14) {
find_diameter();
if (a == i)
return 2;
if (b == i)
return 3;
return (a >> (i - (N - 28))) & 0b1;
}
if (N - 14 <= i && i < N) {
find_diameter();
if (a == i)
return 2;
if (b == i)
return 3;
return (b >> (i - (N - 14))) & 0b1;
}
return 0;
}
pair<int, int> longest_path(vector<int> S)
{
int N = S.size();
int a = 0, b = 0;
for (int i = N - 28; i < N - 14; i++)
a |= S[i] << (i - (N - 28));
for (int i = N - 14; i < N; i++)
b |= S[i] << (i - (N - 14));
for (int i = N - 28; i < N; i++) {
if (S[i] == 2)
a = i;
if (S[i] == 3)
b = i;
}
return {a, b};
}
