錯題--669-修剪二叉搜尋樹.python
阿新 • • 發佈:2018-12-14
正確程式碼:
class Solution: def trimBST(self, root, L, R): """ :type root: TreeNode :type L: int :type R: int :rtype: TreeNode """ if not root: return root if root.val < L: return self.trimBST(root.right, L, R) if root.val > R: return self.trimBST(root.left, L, R) root.left = self.trimBST(root.left, L, R) root.right = self.trimBST(root.right, L, R) return root
#錯題分析 class Solution: def trimBST(self, root, L, R): """ :type root: TreeNode :type L: int :type R: int :rtype: TreeNode """ root = self.fun_2(root, L, R) if root is None: return root self.func_1(root, root.left, L, R) self.func_1(root, root.right, L, R) return root #找根節點 def func_1(self, parent, node, L, R): if node is None: return elif node.val>R: parent.right = node.left elif node.val<L: parent.left = node.right self.func_1(node, node.left, L, R) self.func_1(node, node.right, L, R) #進行裁剪 def fun_2(self, node, L, R): if L<=node.val<=R or node is None: return node elif node.val>R: node = node.left#在這個地方出現問題,缺少了遞迴.. elif node.val<L: node = node.right return self.fun_2(node, L, R)
ps:好菜啊!