Submission #1202179

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
#define pb push_back
#define fs first
#define sc second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
using namespace std;
template<class S,class T> ostream& operator<<(ostream& o,const pair<S,T> &p){return o<<"("<<p.fs<<","<<p.sc<<")";}
template<class T> ostream& operator<<(ostream& o,const vector<T> &vc){o<<"sz = "<<vc.size()<<endl<<"[";for(const T& v:vc) o<<v<<",";o<<"]";return o;}
typedef long long ll;
int N,M;
const int MN=100000;
vector<int> G[MN],rG[MN];
bool vis[MN][3];
ll cnt[3];
ll use;
void dfs(int v,int c){
	if(vis[v][c]) return;
	vis[v][c]=1;
	cnt[c]++;
	for(int u:G[v]) dfs(u,(c+1)%3),use++;
	for(int u:rG[v]) dfs(u,(c+2)%3),use++;
}

int main(){
	cin>>N>>M;
	ll ans=0;
	rep(i,M){
		int x,y;
		cin>>x>>y;
		x--,y--;
		G[x].pb(y);
		rG[y].pb(x);
	}
	rep(v,N) if(!(vis[v][0]||vis[v][1]||vis[v][2])){
		rep(j,3) cnt[j]=0;
		use=0;
		dfs(v,0);
		if(vis[v][0]&&vis[v][1]&&vis[v][2]){
			ans+=cnt[0]*cnt[0];
		}else if(cnt[0]==0||cnt[1]==0||cnt[2]==0){
			ans+=use/2;
		}else{
			ans+=cnt[0]*cnt[1]+cnt[1]*cnt[2]+cnt[2]*cnt[0];
		}
	}
	cout<<ans<<endl;
}

Submission Info

Judge Result