Leetcode 1558. Minimum Numbers of Function Calls to Make Target Array

Starting from zeros, you may increment any single element by 1 or double all elements; find the minimum calls to reach the target array. Key insight: work in binary — total increments = sum of set bits in nums, and total doubles = max bit-length of nums minus one (i.e., floor(log2(max(nums)))) — sum them for the answer.