Minimize the value (hackerearth)

#include<bits/stdc++.h>

using namespace std;

#define ll long long

void dfs(int u, vector< vector<int> > &g, vector<bool> &visited, vector<int> &level){

	visited[u]=true;

	for(int i=0;i<g[u].size();i++){
		int v=g[u][i];

		if(visited[v]==false){
			level[v]=level[u]+1;
			dfs(v,g,visited,level);
		}
	}

	return;
}

void dfs2(int u, vector< vector<int> > &g, vector<bool> &visited, vector<ll> &val){
	visited[u]=true;

	for(int i=0;i<g[u].size();i++){
		int v= g[u][i];

		if(visited[v]==false){
			dfs2(v,g,visited,val);
			val[u]+=val[v];
		}
	}
	return;
}

void solve()
{
    int n,x;
    cin>>n>>x;

    vector< vector<int> > g(n+2, vector<int>() );
    vector<bool> visited(n+2, false);
    vector<ll> val(n+2);

    vector<int>level(n+1);

    for(int i=1;i<n+1;i++){
    	level[i]=0;
    }

    for(int i=1;i<n+1;i++){
    	cin>>val[i];
    }

    val[n+1]=x;

    for(int i=0;i<n-1;i++){
    	int u,v;
    	cin>>u>>v;

    	g[u].push_back(v);
    	g[v].push_back(u);
    }

    dfs(1,g,visited,level);

    int xParent = 0;
    level[xParent]=n+10;

    if(g[1].size()<2){
    	xParent=1;
    }

    for(int i=2;i<n+1;i++){
    	if((g[i].size()<3) && level[xParent]>level[i]){
    		xParent=i;
    	}
    }

    g[xParent].push_back(n+1);

    for(int i=0;i<n+2;i++){
    	visited[i]=false;
    }

    dfs2(1, g, visited,val);

    ll ans=0;

    for(int i=1;i<n+2;i++){
    	ans+=val[i];
    }

    cout<<ans<<endl;


    return;
}

int main()
{
    #ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);
	#endif

    solve();

    
    return 0;
}