Minimum Operations to Halve Array Sum — Python

# Time:  O(nlogn)
# Space: O(n)

import heapq


# heap
class Solution(object):
    def halveArray(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        target = sum(nums)/2.0
        max_heap = [-x for x in nums]
        heapq.heapify(max_heap)
        result = 1
        while max_heap:
            x = -heapq.heappop(max_heap)/2.0
            target -= x
            if target <= 0.0:
                break
            heapq.heappush(max_heap, -x)
            result += 1
        return result