Getting wrong answer for larger value of n

#1 
//k root using binary search
#include<iostream>
#include<cmath>
using namespace std;
int kroot(unsigned long long int n,int k)
{
    unsigned long long int start=0;
    unsigned long long int end=n;
    int ans=-1;
    while (start<=end)
    {
       unsigned long long int mid=(start+end)/2;
         unsigned long long int  o=pow(mid,k);
        
        if (o==n)
        {
            return mid;
        }
        
        if (o<n)
        {   ans=mid;
            start=mid+1;
        }
        else
        {
            end=mid-1;
        }
        
        
    }
   /*  float inc=0.1;
    int precision=3;
    for (int i = 0; i < precision; i++)
    {
        while (ans*ans<n)
        {
            ans=ans+inc;
        }
        ans-=inc;
        inc=inc/10;
    } */
    return ans;
}
int main(){
    unsigned long long int n;
    cin>>n;
    int k;
    cin>>k;
    
    int ans=kroot(n,k);
    cout<<ans;
    
    return 0;
}
#2

overflow may occur because mid^k can be a very large number.(check for case -> 1000000000000000 10 )

use pow function direcly inside if loop without storing it anywhere.

#4

can i store it dynamically??

#5

see this: