Cod sursa(job #3166529)
Utilizator | Ionascu Andrei answar | Data | 8 noiembrie 2023 21:49:54 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.73 kb |
#include <fstream>
#include <algorithm>
using namespace std;
ifstream cin("nrtri.in");
ofstream cout("nrtri.out");
int n,m,i,j,k,s,rez,st,dr,mid,last;
int v[810];
int main () {
cin>>n;
for (i=1;i<=n;i++) {
cin>>v[i];
}
sort(v+1,v+n+1);
for (i=1;i<n-1;i++) {
for (j=i+1;j<n;j++) {
s=v[i]+v[j];
st=j+1;
dr=n;
last=j;
while (st<=dr) {
mid=(st+dr)/2;
if (v[mid]>s) {
dr=mid-1;
}
else {
st=mid+1;
last=mid;
}
}
rez+=last-j;
}
}
cout<<rez;
}