397. Integer Replacement

Given a positive integer n, you can apply one of the following operations:

1. If n is even, replace n with n / 2.
2. If n is odd, replace n with either n + 1 or n - 1.

Return the minimum number of operations needed forn 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

# @lc code=start
using LeetCode

function integer_replacement(n::Int)
    res = 0
    while n != 1
        if iseven(n)
            n >>= 1
        else
            n += (n & 2 == 0 || n == 3) ? -1 : 1
        end
        res += 1
    end
    return res
end
# @lc code=end

integer_replacement (generic function with 1 method)

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