1. 前序遍历(Preorder Traversal): 在前序遍历中,根节点首先被访问,然后按照前序遍历的顺序依次访问左子树和右子树。前序遍历的顺序是:根节点 -> 左子树 -> 右子树。 def preorderTraversal(root): if not root: return [] return [root.val] + preorderTraversal(root.left) + preorderTraversal(root.r...
node=stack.pop()curr=node.rightreturnrsdefpreorderTraversalV4(root):ifnotroot:return[]rs=[]stack=[(root,0)]whilestack:node,visited=stack.pop()ifnode:ifvisited:rs.append(node.val)else:stack.append((node.right,0))stack.append((node.left,0))stack.append((node,1))returnrsdefpreorderTraver...
https://leetcode.com/problems/binary-tree-preorder-traversal/ 题意分析: 前序遍历一棵树,递归的方法很简单。那么非递归的方法呢。 题目思路: 前序遍历的顺序是先遍历根节点,再遍历左子树,最后遍历右子树。递归的方法很直观。非递归的方法是利用栈来实现,后进先出,先放右子树进入栈。代码给的是非递归的方法。
if now==None:returnresultresult.append(now.data) preorderTraversal(now.left,result) preorderTraversal(now.right,result)returnresultprint(preorderTraversal(binaryTree)) 执行结果:[0 , 1, 3, 4 , 2, 5, 6],是不是和我们之前手动遍历的结果一样呢。 中序遍历 中序遍历的顺序是:先遍历树的左节点,...
tree=PerfectBinaryTree() foralphain['A','B','C','D','E','F','G','H','I','J']: tree.append(alpha) print('层次遍历: ',end='') tree.show() print('先序遍历: ',end='') preorder_traversal(tree.get_root()) print() ...
class treeNode: def __init__(self, x): self.val = x self.left = None self.right = None 深度优先搜索（Depth First Search, DFS）非递归的版本在完整代码中前序遍历 PreOrder Traversal：根-左结点-右结点 def preorder(root): if root is None: return [] return [root.val]...
同Construct Binary Tree from Inorder and Postorder Traversal(Python版) # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self.right = right class Solution: def buildTree(self, pre...
# Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution: def inorderTraversal(self, root: TreeNode) -> List[int]: cur=root ...
https://leetcode.com/problems/binary-tree-preorder-traversal/description/ #递归方法classSolution:def__init__(self):self.res=[]defpreorderTraversal(self,root):""" :type root: TreeNode :rtype: List[int] """ifroot:self.res.append(root.val)self.preorderTraversal(root.left)self.preorderTrave...
if__name__=='__main__':tree=PerfectBinaryTree()foralphain['A','B','C','D','E','F','G','H','I','J']:tree.append(alpha)print('层次遍历:',end='')tree.show()print('先序遍历:',end='')preorder_traversal(tree.get_root())print()print('中序遍历:',end='')inorder_tra...