Submission #954747

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
const ll mod=1000000007;
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
// head

const int N=101000;
int n,m,u,v,lab[N],vis[N],val,eg;
ll c[N],ret;
vector<PII> e[N];
void dfs(int u,int d) {
	vis[u]=1; lab[u]=d; c[d]++;
	for (auto p:e[u]) {
		int v=p.fi; eg++;
		if (vis[v]) {
			val&=(lab[v]==(d+p.se)%3);
		} else {
			dfs(v,(d+p.se)%3);
		}
	}
}
int g[110][110];
int main() {
	scanf("%d%d",&n,&m);
//	while (1) {
//	n=5,m=5;
//	rep(i,1,n+1) e[i].clear(),vis[i]=0;
//	rep(i,1,n+1) rep(j,1,n+1) g[i][j]=0;
	rep(i,0,m) {
		scanf("%d%d",&u,&v);
//		u=rand()%n+1,v=rand()%n+1;
//		if (g[u][v]==1) continue;
		e[u].pb(mp(v,1)); e[v].pb(mp(u,2));
//		g[u][v]=1;
//		printf("%d %d\n",u,v);
	}
/*	while (1) {
		bool val=0;
		rep(p,1,n+1) rep(q,1,n+1) rep(r,1,n+1) if (g[p][q]&&g[q][r]&&!g[r][p]) {
			g[r][p]=1; val=1;
		}
		if (!val) break;
	}
	int cnt=0;
	rep(p,1,n+1) rep(q,1,n+1) cnt+=g[p][q];
	printf("%d\n",cnt);*/
	ret=0;
	rep(i,1,n+1) if (!vis[i]) {
		c[0]=c[1]=c[2]=0;
		val=1; eg=0;
		dfs(i,0);
		if (val) {
			if (c[2]&&c[1]) ret+=c[0]*c[1]+c[1]*c[2]+c[2]*c[0];
			else ret+=eg/2;
		} else ret+=(c[0]+c[1]+c[2])*(c[0]+c[1]+c[2]);
	}
	printf("%lld\n",ret);
	//assert(ret==cnt);
//}
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:43:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
./Main.cpp:49:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&u,&v);
                      ^

Judge Result