1046. Last Stone Weight

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class Solution:
    def lastStoneWeight(self, stones: List[int]) -> int:
        heap = []
        for stone in stones:
            heapq.heappush(heap, -1 * stone)
        
        while len(heap) > 1:
            first = heapq.heappop(heap)
            second = heapq.heappop(heap)
            if first != second:
                heapq.heappush(heap, first - second)
        
        if len(heap) == 0:
            return 0
        else:
            return -1 * heap[0]