Create compare_2_tops.py

heaps/compare_2_tops.py

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+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+```
+You are given an array of integers stones where 
+stones[i] is the weight of the ith stone.
+
+We are playing a game with the stones. On each turn, 
+we choose the heaviest two stones and smash them together. 
+Suppose the heaviest two stones have weights x and y with 
+x <= y. The result of this smash is:
+
+If x == y, both stones are destroyed, and
+If x != y, the stone of weight x is destroyed, and the stone 
+of weight y has new weight y - x.
+At the end of the game, there is at most one stone left.
+
+Return the weight of the last remaining stone. 
+If there are no stones left, return 0.
+```
+
+def last_stone(stones) -> int:
+
+        for i in range(len(stones)):
+            stones[i] *= -1
+
+        heapq.heapify(stones)
+
+        while len(stones) > 1:
+
+            stone_1 = heapq.heappop(stones)
+            stone_2 = heapq.heappop(stones)
+
+            if stone_1 != stone_2:
+                heapq.heappush(stones, stone_1 - stone_2)
+
+        if stones:
+            return -heapq.heappop(stones)
+            
+        else:
+            return 0
+