Cod sursa(job #942738)

Utilizator geniucosOncescu Costin geniucos Data 23 aprilie 2013 12:51:55
Problema Triplete Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.01 kb
#include<cstdio>
#include<vector>
using namespace std;
int sf,n,m,i,x1,y1,j,k,nrb[4100],pr[5000],su[5000];
long long nr;
unsigned int a[4099][170];
vector < int > v[4099];
vector < int >::iterator it;
void bag(int x,int y)
{
    a[x][su[y]]|=(1LL<<(pr[y]));
    if(y>x) v[x].push_back(y);
}
int nrbb(long long val)
{
    int s=0;
    while(val)
    {
        s+=nrb[val&4095];
        val>>=12;
    }
    return s;
}
int main()
{
freopen("triplete.in","r",stdin);
freopen("triplete.out","w",stdout);
scanf("%d",&n);
scanf("%d",&m);
for(i=1;i<=n;i++)
{
    su[i]=i/30;
    pr[i]=i%30;
}
for(i=1;i<=m;i++)
{
    scanf("%d",&x1);
    scanf("%d",&y1);
    bag(x1,y1);
    bag(y1,x1);
}
for(i=1;i<=(1<<12);i++)
{
    if(i&1) nrb[i]=nrb[i>>1]+1;
    else nrb[i]=nrb[i>>1];
}
sf=n/30;
if(n%30!=0) sf++;
for(i=1;i<=n;i++)
    for(it=v[i].begin();it!=v[i].end();it++)
    {
        for(k=sf;k>=0;k--)
            nr+=nrbb(a[i][k]&a[*it][k]);
    }
printf("%lld\n",nr/3);
return 0;
}