165B. Burning Midnight Oil - Codeforces Solution C++

➤  Problem Link : 165B. Burning Midnight Oil 

✅ C++ Solution :

 
#include<bits/stdc++.h>
using namespace std;

#define ll long long int

bool func(ll v,ll n,ll k)
{
	ll p = (floor)((double)log(v)/log(k));
	double d = pow(k,p+1);
	d=1/d;
	d-=1;
	d/=(1-k);
	d*=(v*k);
	if(d>=n)
		return true;
	return false;
	
}

bool check(ll x,ll n,ll k)
{
	ll sum=x;
	ll t=k;
	while(k<=x)
	{
		sum+=x/k;
		k*=t;
	}
	if(sum>=n)
		return true;
	return false;
}

int main()
{
	ll n,k;
	cin>>n>>k;
	if(n<k)
	{
	    cout<<n;
	    exit(0);
	}
	ll low,mid,high;
	low=0;
	high=1000000000;
	while(low<high)
	{
		mid=low+(high-low)/2;
		if(func(mid,n,k))
			high=mid;
		else
			low=mid+1;
	}
	for(ll x=low;;x++)
	{
		if(check(x,n,k))
		{
			cout<<x;
			break;
		}
	}
	
}

 

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About Utkarsh Gupta

I am a Member Technical at D.E. Shaw India Pvt. Ltd. CodingWithArt is a blog where you find tricks and solutions to challenging coding and development problems. I aim to build a universal tech platform for every enthusiast out there.