Submission #1004307

---

Source Code Expand

#include <algorithm>  
#include <iostream>  
#include <sstream>  
#include <string>  
#include <cstring>
#include <vector>  
#include <queue>  
#include <set>  
#include <map>  
#include <cstdio>  
#include <cstdlib>  
#include <cctype>  
#include <cmath>  
#include <list>  
#include <cassert>
#include <ctime>
#include <climits>
using namespace std;  

#define PB push_back  
#define MP make_pair  
#define SZ(v) ((int)(v).size())  
#define FOR(i,a,b) for(int i=(a);i<(b);++i)  
#define REP(i,n) FOR(i,0,n)  
#define FORE(i,a,b) for(int i=(a);i<=(b);++i)  
#define REPE(i,n) FORE(i,0,n)  
#define FORSZ(i,a,v) FOR(i,a,SZ(v))  
#define REPSZ(i,v) REP(i,SZ(v))  
typedef long long ll;
typedef unsigned long long ull;
ll gcd(ll a,ll b) { return b==0?a:gcd(b,a%b); }

const int MAXN=100000;
const int MAXM=100000;

int n,m;
int ghead[MAXN],gnxt[2*MAXM],gto[2*MAXM];

bool done[MAXN];
int col[MAXN];
int q[MAXN],qhead,qtail;
int cnt[3],haven,havem;
ll process(int s) {
	qhead=qtail=0; cnt[0]=cnt[1]=cnt[2]=haven=havem=0; done[s]=true,col[s]=0,q[qhead++]=s,++cnt[0];
	bool ok=true;
	while(qtail<qhead) {
		int at=q[qtail++]; ++haven;
		for(int x=ghead[at];x!=-1;x=gnxt[x]) {
			++havem;
			int to=gto[x];
			if(ok) {
				int want=(col[at]+1+x%2)%3;
				if(col[to]==-1) col[to]=want,++cnt[want]; else if(col[to]!=want) ok=false;
			}
			if(!done[to]) done[to]=true,q[qhead++]=to;
		}
	}
	//printf("%d ok=%d haven=%d havem=%d cnt=%d %d %d\n",s,ok?1:0,haven,havem,cnt[0],cnt[1],cnt[2]);
	if(!ok) return (ll)haven*haven;
	if(cnt[0]==0||cnt[1]==0||cnt[2]==0) return havem/2;
	return (ll)cnt[0]*cnt[1]+(ll)cnt[1]*cnt[2]+(ll)cnt[2]*cnt[0];
}

void run() {
	scanf("%d%d",&n,&m); REP(i,n) ghead[i]=-1,done[i]=false,col[i]=-1;
	REP(i,m) {
		int a,b; scanf("%d%d",&a,&b); --a,--b;
		gnxt[2*i+0]=ghead[a],ghead[a]=2*i+0,gto[2*i+0]=b;
		gnxt[2*i+1]=ghead[b],ghead[b]=2*i+1,gto[2*i+1]=a;
	}
	ll ret=0;
	REP(i,n) if(!done[i]) ret+=process(i);
	printf("%lld\n",ret);
}

int main() {
	run();
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void run()’:
./Main.cpp:65:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m); REP(i,n) ghead[i]=-1,done[i]=false,col[i]=-1;
                     ^
./Main.cpp:67:31: 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