1342. Number of Steps to Reduce a Number to Zero

题目

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 <= 106

题目大意

给你一个数，偶数除2，奇数-1，几步才能得到0

解题思路

• 简单题，按照题意依次循环计算前缀和即可。

代码

First Commit

func numberOfSteps(num int) int {
	var steps int
	for num > 0 {
		steps += 1
		if num%2 == 0 {
			num = num / 2
		} else {
			num = num - 1
		}
	}
	return steps
}