Cod sursa(job #2664821)
Utilizator | Lazar Razvan Gabriel RazvanLazar2004 | Data | 29 octombrie 2020 15:27:03 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.79 kb |
#include <fstream>
#include<algorithm>
using namespace std;
int v[801];
int main()
{
ifstream in("nrtri.in");
ofstream out("nrtri.out");
long long int n,l=0,t=1;
in>>n;
while(t*2<=n){
t*=2;
}
for(long long int i=1;i<=n;i++){
in>>v[i];
}
sort(v+1,v+n+1);
for(long long int i=1;i<=n-2;i++){
for(long long int j=i+1;j<=n-1;j++){
long long int a=v[i]+v[j];
if(a<v[n]){
long long int r=0;
for(long long int k=t;k>0;k/=2){
if(v[r+k]<=a && r+k<=n){
r+=k;
}
}
l+=(r-j);
}else{
l+=(n-j);
}
}
}
out<<l;
}