Python 实现树前序后序遍历

正所谓人生苦短，我用 Python , 下面使用 Python 实现 先序遍历 和 后序遍历 ，代码也是相当简洁

树结构

下面以这颗树的结构为例：

     1
    /|\
   2 3 4 
     /\
    5  6 

具体代码

import networkx as nx
import matplotlib.pyplot as plt

class Node:
    def __init__(self, val:int) -> None:
        self.val = val
        self.children = []
        pass

class Solution:

    def preorder(self, root: Node)->list[int]:
        """
        先序遍历
        """
        def dfs(root, ans):
            if not root: return
            ans.append(root.val)
            for child in root.children:
                dfs(child, ans)
            
        ans:list[int] = []
        dfs(root, ans)
        return ans
    
    def postorder(self, root: Node)->list[int]:
        """
        后序遍历
        """
        def dfs(root, ans):
            if not root: return
            for child in root.children:
                dfs(child, ans)
            ans.append(root.val)
        ans:list[int] = []
        dfs(root, ans)
        return ans


# 构建树结构为
#     1
#    /|\
#   2 3 4 
#     /\
#    5  6 

root = Node(1)

node2 = Node(2)
node3 = Node(3)
node4 = Node(4)
node5 = Node(5)
node6 = Node(6)

root.children.append(node2)
root.children.append(node3)
root.children.append(node4)

node3.children.append(node5)
node3.children.append(node6)

print("先序遍历")
print(Solution().preorder(root=root))
print("后序遍历")
print(Solution().postorder(root=root))