Cod sursa(job #402772)

Utilizator vlad.doruIon Vlad-Doru vlad.doru Data 24 februarie 2010 09:56:29
Problema Triplete Scor 20
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.92 kb
#include <fstream>

using namespace std;

ifstream in("triplete.in");
ofstream out("triplete.out");

const int N=1<<13;
const int B=8;
const int M=1<<17;
unsigned char a[N][N>>3];
unsigned int n,m;

struct muchie{
	unsigned short int x,y;
};
muchie v[M];

inline unsigned int comp(unsigned int x){
	return x>>3;
}

inline unsigned int bit(unsigned int x){
	return x & 7;
}
 
void citire(){
	in>>n>>m;
	for(unsigned int i=0;i<m;++i){
		in>>v[i].x>>v[i].y;
		--v[i].x;
		--v[i].y;
		a[v[i].x][comp(v[i].y)]|=(1<<bit(v[i].y));
		a[v[i].y][comp(v[i].x)]|=(1<<bit(v[i].x));
	}
}

inline unsigned int nrbiti(unsigned char x){
	unsigned int nr=0;
	while(x){
		++nr;
		x&=(x-1);
	}
	return nr;
}

int main(){
	citire();
	unsigned int i,j,k=m>>3,s=0;
	for(i=0;i<m;++i){
		for(j=0;j<=k;j++){
			s+=nrbiti(a[v[i].x][j]&a[v[i].y][j]);
		}
	}
	out<<s/3<<"\n";
	in.close();
	out.close();
	return 0;
}