- Difficulty: Medium
- Tags: LeetCode, Medium, Greedy, Bit Manipulation, Memoization, Dynamic Programming, leetcode-397, O(n), O(1), Math
Problem
Given a positive integer n
, you can apply one of the following operations:
- If
n
is even, replacen
withn / 2
. - If
n
is odd, replacen
with eithern + 1
orn - 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
Constraints:
1 <= n <= 231 - 1