1342.go

// Source: https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero
// Title: Number of Steps to Reduce a Number to Zero
// Difficulty: Easy
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Given an integer num, return the number of steps to reduce it to zero.
//
// In one step, 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.
//
// Example 2:
//
//   Input: num = 8
//   Output: 4
//   Explanation:
//   Step 1) 8 is even; divide by 2 and obtain 4.
//   Step 2) 4 is even; divide by 2 and obtain 2.
//   Step 3) 2 is even; divide by 2 and obtain 1.
//   Step 4) 1 is odd; subtract 1 and obtain 0.
//
// Example 3:
//
//   Input: num = 123
//   Output: 12
//
// Constraints:
//
//   0 <= num <= 10^6
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

func numberOfSteps(num int) int {
	step := 0
	for ; num > 0; step++ {
		if num%2 == 0 { // Even
			num >>= 1
		} else { // Odd
			num--
		}
	}

	return step
}