1342. Number of Steps to Reduce a Number to Zero

package LeetCode_1342

/**
 * 1342. Number of Steps to Reduce a Number to Zero
 * https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/
 * Given a non-negative integer num, return the number of steps to reduce it to zero.
 * If the current number is even, you have to divide it by 2, otherwise, you have to subtract 1 from it.
Example 1:
Input: num = 14
Output: 6
Explanation:
Step 1) 14 is even; divide by 2 and obtain 7.
Step 2) 7 is odd; subtract 1 and obtain 6.
Step 3) 6 is even; divide by 2 and obtain 3.
Step 4) 3 is odd; subtract 1 and obtain 2.
Step 5) 2 is even; divide by 2 and obtain 1.
Step 6) 1 is odd; subtract 1 and obtain 0.
 * */
class Solution {
    /*
    * solution: follow by:
    * If the current number is even, you have to divide it by 2, otherwise, you have to subtract 1 from it.
    * Time:O(logn), Space:O(1)
    * */
    fun numberOfSteps(num: Int): Int {
        var result = 0
        var n = num
        while (n != 0) {
            if (n % 2 == 0) {
                n /= 2
            } else {
                n -= 1
            }
            result++
        }
        return result
    }
}