Submission #2561228

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int ab(int x){return x>0?x:-x;}
vector<int> G[100005];
int f[100005];
int dfs(int x,int fa)
{
	f[x]=-1;
	for(int v:G[x])
		if(v!=fa)
			f[x]-=dfs(v,x);
	return f[x];
}
int main()
{
	ios::sync_with_stdio(0);
	int n,m; cin>>n>>m;
	for(int i=1,u,v;i<=m;i++)
		cin>>u>>v,G[u].push_back(v),G[v].push_back(u);
	
	if(!dfs(1,0)) {
		ll ans=0;
		for(int i=1;i<=n;i++)
			ans+=ab(f[i]);
		cout<<ans<<endl;
	} else 
		cout<<-1<<endl;
	return 0;
}

Submission Info

Judge Result