number-of-steps-to-reduce-a-number-to-zero.py

"""

1342. Number of Steps to Reduce a Number to Zero
Easy

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

"""

# V0
# IDEA : brute force
class Solution:
    def numberOfSteps (self, num):
        count = 0
        
        while(num!=0):
            if num%2 == 0:
                num = num // 2
            else:
                num = num - 1
            count += 1
            
        return count

# V1
# IDEA : brute force
# https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/discuss/721004/Easy-Python-Solution
class Solution:
    def numberOfSteps (self, num):
        count = 0
        
        while(num!=0):
            if num%2 == 0:
                num = num // 2
            else:
                num = num - 1
            count += 1
            
        return count

# V1
# IDEA : bit op
class Solution:
    def numberOfSteps(self, num):
        c=0
        while num:
            if(num%2!=0):
                c+=1
                num=num-1
                continue
            num=num>>1
            c+=1
        return c

# V2