Submission #1156775

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Source Code Expand

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<cassert>
#define PB push_back
#define MP make_pair
#define sz(v) (in((v).size()))
#define forn(i,n) for(in i=0;i<(n);++i)
#define forv(i,v) forn(i,sz(v))
#define fors(i,s) for(auto i=(s).begin();i!=(s).end();++i)
#define all(v) (v).begin(),(v).end()
using namespace std;
typedef long long in;
typedef vector<in> VI;
typedef vector<VI> VVI;
VI vis;
VVI egs;
bool dfs(in u, in typ){
  if(vis[u]){
    if(vis[u]==typ)
      return 1;
    return 0;
  }
  vis[u]=typ;
  bool notbip=0;
  forv(i,egs[u]){
    if(!dfs(egs[u][i],3-typ))
      notbip=1;
  }
  return !notbip;
}
in nbip=0;
in nus=0;
in nsing=0;
int main(){
  ios::sync_with_stdio(0);
  cin.tie(0);
  in n,m;
  cin>>n>>m;
  egs.resize(n);
  vis.resize(n);
  in ta,tb;
  forn(zz,m){
    cin>>ta>>tb;
    --ta;
    --tb;
    egs[ta].PB(tb);
    egs[tb].PB(ta);
  }
  forn(i,n){
    if(vis[i])
      continue;
    if(sz(egs[i])==0){
      vis[i]=3;
      ++nsing;
      continue;
    }
    if(dfs(i,1))
      ++nbip;
    else
      ++nus;
  }
  in sm=0;
  sm+=2*nsing*n-nsing*nsing;
  sm+=nus*nus+2*nus*nbip;
  sm+=2*nbip*nbip;
  cout<<sm<<endl;
  return 0;
}

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