Sqrt(x)

Description

Implement int sqrt(int x).

Compute and return the square root of x, where x is guaranteed to be a non-negative integer.

Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.

Example 1:

Input: 4
Output: 2

Example 2:

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since 
             the decimal part is truncated, 2 is returned.

Solution(javascript)

/**
 * @param {number} x
 * @return {number}
 */
// const mySqrt = (x) => {
//   const aux = (low, high) => {
//     if (low > high) {
//       return null
//     }
//     const middle = Math.floor((low + high) / 2)
//     const left = middle - 1
//     const right = middle + 1
//     if ((middle * middle <= x) && (right * right > x)) {
//       return middle
//     }
//     if (middle * middle < x) {
//       return aux(right, high)
//     }
//     return aux(low, left)
//   }
//   return aux(0, x)
// }


const mySqrt = (x) => {
  let r = x
  while (r * r > x) {
    r = Math.floor((r + x / r) / 2)
  }

  return r
}