Submission #1246350

---

Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define MAX 114514
vector<int> G[MAX];
int de[MAX],pa[MAX];
int ans;
void dfs(int v,int p,int d){
  de[v]=d;
  pa[v]=p;
  for(int u:G[v]){
    if(u==p) continue;
    if(de[u]<0) dfs(u,v,d+1);
    else{
      //cout<<de[v]<<" "<<de[u]<<endl;
      ans=de[v]-de[u]+1;
      return;
    }
    if(~ans) return;
  }
  if(~ans) return;
}
signed main(){
  memset(de,-1,sizeof(de));
  int n;
  cin>>n;
  for(int i=0;i<n;i++){
    int x,y;
    cin>>x>>y;
    x--;y--;
    G[x].push_back(y);
    G[y].push_back(x);
  }
  ans=-1;
  dfs(0,-1,0);
  cout<<ans<<endl;
  return 0;
}

Submission Info

Judge Result