Codeforces Round #146 (Div. 2) 236B. Easy Number Challenge Solution

Problem Link:  https://codeforces.com/problemset/problem/236/B

Solution in C++:

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

///**********ALLAH IS ALMIGHTY************///

#include <bits/stdc++.h>

using namespace std;

#define ll long long int

ll d[1000009];

int main()

{

    ios_base::sync_with_stdio(0);

    cin.tie(0);

    ll a,b,c,i,j,k;

    cin>>a>>b>>c;

    for(i=1; i<=1000000; i++)

    {

        for(j=i; j<=1000000; j+=i)

        {

            d[j]++;

        }

    }

    ll ans=0;

    for(i=1; i<=a; i++)

    {

        for(j=1; j<=b; j++)

        {

            for(k=1; k<=c; k++)

            {

              ans=(ans+d[i*j*k])%1073741824 ;

            }

        }

    }

    cout<<ans<<endl;

}