P7991 [USACO21DEC] Connecting Two Barns S

debug了一天，人已经没了。(T_T)哪位大佬能帮忙看看哪里错了：

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;

void find(int node, vector<int>& g, vector<int>* adj, bool* vis){
	g.push_back(node);
	vis[node]=1;
	for(auto u : adj[node]){
		if(!vis[u]){
			find(u, g, adj, vis);
		}
	}
}
  
void solve(){
	int n, m; cin>>n>>m;
	vector<int> adj[n+5];
	bool vis[n+5];
	memset(vis, 0, sizeof(vis));
	for(int i=0;i<m;i++){
		int a,b; cin>>a>>b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	vector<int> F, G;
	find(1, F, adj, vis), find(n, G, adj, vis);
	sort(F.begin(), F.end());
	sort(G.begin(), G.end());

	long long cost=1e11;

	for(int i=1;i<=n;i++){
		//与1的连通块
		bool c=1;
		long long costOne, costN;
		if(c){
			long long c1=1e11, c2=1e11, closestIdx=upper_bound(F.begin(), F.end(), i)-F.begin();
			if(closestIdx<F.size()) c2=pow(abs(i-F[closestIdx]), 2);
			
			if(closestIdx-1>=0) c1=pow(abs(i-F[closestIdx-1]), 2);			
			costOne=min(c1, c2);
		}
 		//与n的连通块
		if(c){
			//与n的component
			long long c1=1e11, c2=1e11, closestIdx=upper_bound(G.begin(), G.end(), i)-G.begin();
			if(closestIdx<G.size()) c2=pow(abs(i-G[closestIdx]), 2);
			if(closestIdx-1>=0) c1=pow(abs(i-G[closestIdx-1]), 2);
			costN=min(c1, c2);
		}
		cost=min(cost, costOne+costN);
	}
	cout<<cost<<endl;
}

int main(){
	int t; cin>>t;
	while(t--){
		solve();
	}
}