Submission #966196

---

Source Code Expand

#define DEB
#include<bits/stdc++.h>
#define REP(i,m) for(int i=0;i<(m);++i)
#define REPN(i,m,in) for(int i=(in);i<(m);++i)
#define ALL(t) (t).begin(),(t).end()
#define CLR(a) memset((a),0,sizeof(a))
#define pb push_back
#define mp make_pair
#define fr first
#define sc second

using namespace std;


#ifdef DEB
#define dump(x)  cerr << #x << " = " << (x) << endl
#define prl cerr<<"called:"<< __LINE__<<endl
template<class T> void debug(T a,T b){ for(;a!=b;++a) cerr<<*a<<' ';cerr<<endl;}
#else
#define dump(x) ;
#define prl ;
template<class T> void debug(T a,T b){ ;}
#endif

template<class T> void chmin(T& a,const T& b) { if(a>b) a=b; }
template<class T> void chmax(T& a,const T& b) { if(a<b) a=b; }

typedef long long int lint;
typedef pair<int,int> pi;

namespace std{
  template<class S,class T>
  ostream &operator <<(ostream& out,const pair<S,T>& a){
    out<<'('<<a.fr<<','<<a.sc<<')';
    return out;
  }
}

//const int INF=5e8;

struct uf{
  static const int MAXN=100005;
  int par[MAXN];
  int size[MAXN];
  void init(){
    memset(par,-1,sizeof(par));
    REP(i,MAXN) size[i]=1;
  }
  int root(int a){
    if(par[a]==-1) return a;
    return par[a]=root(par[a]);
  }
  void unite(int a,int b){
    a=root(a);b=root(b);
    if(a==b) return;
    if(size[a]<size[b]) swap(a,b);

    par[b]=a;
    size[a]+=size[b];
  }
  bool same(int a,int b){
    return root(a)==root(b);
  }
};

uf u;
int n,m;
vector<pi> g[100005];
int col[100005];

bool fail;
lint mark[3];
int E;
void dfs(int v){
  mark[col[v]]++;
  for(auto e:g[v]){
    ++E;
    if(~col[e.fr] && col[e.fr]!=(col[v]+e.sc)%3) fail=true;
    if(col[e.fr]==-1){
      col[e.fr]=(col[v]+e.sc)%3;
      dfs(e.fr);
    }
  }
}

int main(){
  u.init();
  cin>>n>>m;
  REP(i,m){
    int a,b;scanf("%d%d",&a,&b);--a;--b;
    g[a].pb(mp(b,1));
    g[b].pb(mp(a,2));
    u.unite(a,b);
  }
  memset(col,-1,sizeof(col));
  lint res=0;
  REP(i,n) if(u.root(i)==i){
    col[i]=0;
    CLR(mark);
    E=0;
    fail=false;
    dfs(i);
    if(fail){
      lint s=u.size[i];
      res+=s*s;
    }else if(mark[0] && mark[1] && mark[2]){
      res+=mark[0]*mark[1]+mark[1]*mark[2]+mark[2]*mark[0];
    }else{
      res+=E/2;
    }
  }
  cout<<res<<endl;
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:90:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     int a,b;scanf("%d%d",&a,&b);--a;--b;
                                ^

Judge Result