Cod sursa(job #3262645)
Utilizator | Data | 11 decembrie 2024 09:09:29 | |
---|---|---|---|
Problema | Pairs | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.59 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream f("pairs.in");
ofstream g("pairs.out");
const int NMAX=1e6;
long long n,maxim,v[NMAX+1],fr[NMAX+1];
int main()
{
f>>n;
for(int i=1;i<=n;i++)
{
long long x;
f>>x;
fr[x]++;
maxim=max(maxim,x);
}
for(int i=maxim;i>=1;i--)
{
for(int j=1;j*i<=maxim;j++)
{
v[i]+=fr[j*i];
}
v[i]=v[i]*(v[i]-1)/2;
for(int j=2;j*i<=maxim;j++)
{
v[i]-=v[j*i];
}
}
g<<v[1];
return 0;
}