Cod sursa(job #153808)

Utilizator andrei-alphaAndrei-Bogdan Antonescu andrei-alpha Data 10 martie 2008 19:03:51
Problema Numarare triunghiuri Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.82 kb
#include <stdio.h>
#define N 812
int v[N];
int rez,i,j,k,n;
int caut(int p, int u, int i)
{
	int m,n,j;
	j=p; n=u;
	m=(p+u)/2;
	while (p<=u)
	{
		if ((v[m]<=v[i]+v[j] && v[m+1]>v[i]+v[j]) || (v[m]<=v[i]+v[j] && m==n))
			return m; 
		else 
			if (v[m]<=v[i]+v[j] && v[m+1]<=v[i]+v[j])
			{ p=m+1; m=(p+u)/2; }
			else 
			{ u=m-1; m=(p+u)/2; } 
	}
  return 0;
}


int main()
{
	int inj,gata,aux;
	freopen("nrtri.in", "r", stdin);
	freopen("nrtri.out", "w",stdout);
	scanf("%d", &n);
	for(i=1;i<=n;++i)
		scanf("%d", &v[i]);
	
	inj=n; while(inj>1)
	{inj/=2; do{gata=1;
	for(i=1;i<=n-inj;i++)
	if(v[i]>v[i+inj]) {
	aux=v[i]; v[i]=v[i+inj];
	v[i+inj]=aux; gata=0; }	
	}while(!gata);} 
	
	for (i=1;i<n-1;++i)
		for (j=i+1;j<n;++j)
		{ k=caut(j,n,i); rez+=(k-j); }
	printf("%d\n", rez);
	return 0;
}