Given a positive integer n, you can apply one of the following operations:
If n is even, replace n with n / 2. If n is odd, replace n with either n + 1 or n - 1. Return the minimum number of operations needed for n to become 1.
Example 1:
Input: n = 8
Output: 3
Explanation: 8 -> 4 -> 2 -> 1
Example 2:
Input: n = 7
Output: 4
Explanation: 7 -> 8 -> 4 -> 2 -> 1
or 7 -> 6 -> 3 -> 2 -> 1
Example 3:
Input: n = 4
Output: 2
Solution
class Solution:
def integerReplacement(self, n: int) -> int:
cnt = 0
while n > 1:
if n % 2 == 0:
n = n / 2
elif n % 4 == 1 or n == 3:
n -= 1
else:
n += 1
cnt += 1
return cnt