describe

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.	
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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.
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Example 3:

Input: num = 123
Output: 12
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Note:

0 <= num <= 10^6
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parsing

If num is even, divide by two; otherwise, subtract by one until num is 0. Count each operation to get the final result.

answer

class Solution(object): def numberOfSteps (self, num): """ :type num: int :rtype: int """ res = 0 while num! =0: if num%2==0: num /= 2 res += 1 else: num -= 1 res += 1 return resCopy the code

The results

Runtime: 10 ms, faster than 76.09% of Python online submissions for Number of Steps to Reduce a Number to Zero. Memory Usage: Given in the Python online submissions for Number of Steps to Reduce a Number to Zero.Copy the code

Original link: leetcode.com/problems/nu…

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