Root of number - mock interview 12:00 PM -

rootOfNumber.cs

import java.io.*;
import java.util.*;

class Solution {
  static double root(double x, int n) {
    if (x == 0 || x == 1){
      return x;
    }
    
    if (n == 1){
      return x;
    }
    
    double lo = 0;
    double hi = Math.max(1, x);
    
    int iterations = 200;
    double guess = 0;
    while(iterations > 0){
      iterations--;
      guess = lo + (hi-lo)/2;
      
      double guessResult = exp(guess,n);
      if (guessResult <= 0 || guessResult > x){
        hi = guess;
      } else {
        lo = guess;
      }
    }
    
    return guess;
  }
  
  private static double exp(double x, int n){
    if (n == 1) {
      return x;
    }
    
    double result = 1;
    double base = x;
    while(n > 0){
      if ((n&1) != 0){
        result *= base;
      }
      base *= base;
      n >>= 1;
    }
    
    return result;
  }       

  public static void main(String[] args) {
  }
}