AtCoder Beginner Contest 246 D - 2-variable Function Solution

 

Problem Link:  https://atcoder.jp/contests/abc246/tasks/abc246_d

 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 mx 1e6

long long fun(long long a,long long b)

{

    return a*a*a+a*a*b+a*b*b+b*b*b;

}

int main()

{

    long long  n,i,j,x,r,a,b;

    cin>>n;

    j=mx;

    if(n<mx)

    j=n;

    x=9e18;

    for(i=0; i<=mx; i++)

    {

        while((fun(i,j)>=n)&&(j>=0))

        {

            x=min(x,fun(i,j));

            j--;

        }

        if(j<0)

        break;

    }

    cout<<x<<endl;

}