Cod sursa(job #2883936)

Utilizator vladburacBurac Vlad vladburac Data 1 aprilie 2022 23:47:30
Problema Mins Scor 0
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.7 kb
#include <iostream>
#include <fstream>
#define int long long
using namespace std;
const int MAXN = 1e6;

ifstream fin( "mins.in" );
ofstream fout( "mins.out" );

// trebuie sa determinam toate fractiile ireductibile a / b
int divprimi[MAXN+1];
signed main() {
  int n, m, gcd, fractiiIred, nr, i, j;
  for( i = 2; i <= MAXN; i++ ) {
    if( divprimi[i] == 0 ) {
      for( j = i; j <= MAXN; j += i )
        divprimi[j]++;
    }
  }
  fin >> n >> m;
  fractiiIred = 0;
  for( gcd = 1; gcd <= min( n, m ); gcd++ ) {
    nr = ( ( n - 1 ) / gcd ) * ( ( m - 1 ) / gcd );
    if( divprimi[gcd] % 2 == 1 )
      fractiiIred -= nr;
    else
      fractiiIred += nr;
  }
  fout << fractiiIred;
}