2020-03-19

Author: JiayangWu

1380.矩阵中的幸运数/1380-矩阵中的幸运数.py

@@ -0,0 +1,15 @@
+class Solution(object):
+    def luckyNumbers (self, matrix):
+        """
+        :type matrix: List[List[int]]
+        :rtype: List[int]
+        """
+        row, col = set(), set()
+        
+        for r in matrix:
+            row.add(min(r))
+
+        for c in zip(*matrix):
+            col.add(max(c))
+        
+        return list(row & col)

1381.设计一个支持增量操作的栈/1381-设计一个支持增量操作的栈.py

@@ -0,0 +1,38 @@
+class CustomStack(object):
+
+    def __init__(self, maxSize):
+        """
+        :type maxSize: int
+        """
+        self.stack = []
+        self.maxSize = maxSize
+    def push(self, x):
+        """
+        :type x: int
+        :rtype: None
+        """
+        if len(self.stack) < self.maxSize:
+            self.stack.append(x)
+
+    def pop(self):
+        """
+        :rtype: int
+        """
+        return self.stack.pop() if self.stack else -1
+
+
+    def increment(self, k, val):
+        """
+        :type k: int
+        :type val: int
+        :rtype: None
+        """
+        for i in range(min(k, len(self.stack))):
+            self.stack[i] += val
+
+
+# Your CustomStack object will be instantiated and called as such:
+# obj = CustomStack(maxSize)
+# obj.push(x)
+# param_2 = obj.pop()
+# obj.increment(k,val)

1382.将二叉搜索树变平衡/1382-将二叉搜索树变平衡.py

@@ -0,0 +1,30 @@
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def balanceBST(self, root):
+        """
+        :type root: TreeNode
+        :rtype: TreeNode
+        """
+        def inorder(node):
+            if not node:
+                return []
+            return inorder(node.left) + [node.val] + inorder(node.right)
+        
+        l = inorder(root)
+        
+        def generator(l):
+            if not l:
+                return None
+            idx = len(l) // 2
+            root = TreeNode(l[idx])
+            root.left = generator(l[:idx])
+            root.right = generator(l[idx + 1:])
+            return root
+            
+        return generator(l)

1383.最大的团队表现值/1383-最大的团队表现值.py

@@ -0,0 +1,29 @@
+class Solution(object):
+    def maxPerformance(self, n, speed, efficiency, k):
+        """
+        :type n: int
+        :type speed: List[int]
+        :type efficiency: List[int]
+        :type k: int
+        :rtype: int
+        """
+        from heapq import *
+        combine = [(speed[i], efficiency[i]) for i in range(n)]
+        combine = sorted(combine, key = lambda x: - x[1])
+        res = 0
+        MOD = 10 ** 9 + 7
+        min_heap = []
+        speed_sum = 0
+        for i in range(n):
+            s, e = combine[i]
+            if len(min_heap) < k:
+                heappush(min_heap, s)
+                speed_sum += s
+            else:
+                if min_heap and min_heap[0] < s:
+                    speed_sum = speed_sum - min_heap[0] + s
+                    heappush(min_heap, s)
+                    heappop(min_heap)
+                    
+            res = max(res, speed_sum * e)
+        return res % MOD

面试题40.最小的k个数/面试题40-最小的k个数.py

@@ -5,4 +5,14 @@ def getLeastNumbers(self, arr, k):
         :type k: int
         :rtype: List[int]
         """
-        return sorted(arr)[:k]
+        from heapq import * 
+        
+        queue = []
+        for num in arr:
+            if len(queue) < k:
+                heappush(queue, -num)
+            else:
+                if queue and queue[0] < num:
+                    heappush(queue, -num)
+                    heappop(queue)
+        return [-item for item in queue]