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
SOLUTION:
class Solution:
def numberOfSteps(self, num: int) -> int:
steps = 0
while num > 0:
if num & 1:
num = (num - 1) // 2
steps += 1 if num == 0 else 2
else:
num = num // 2
steps += 1
return steps
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