题解 | #二叉树遍历#

import sys
def creat(node,preorder,inorder,index):
    j=0
    node.val=preorder[index]
    left=[]

    for j in range(len(inorder)):
        if(inorder[j]==node.val):
            break
        else: left.append(inorder[j])
    if(j+1<len(inorder)):right=inorder[j+1:]
    else:right=[]
    if(len(left)):
        node.left=TreeNode()
        index=creat(node.left,preorder,left,index+1)
    if(len(right)):
        node.right=TreeNode()
        index=creat(node.right,preorder,right,index+1)
    return index
    
def postorder(Tree):
    if(Tree):
        postorder(Tree.left)
        postorder(Tree.right)
        print(Tree.val,end='')
        
class TreeNode(object):
    def __init__(self, val=''):
        self.val = val
        self.left = None
        self.right = None

for line in sys.stdin:
    preorder = list(line)
    preorder.pop()
    inorder= list(input())
    #print(preorder,inorder)
    Tree = TreeNode() #实例化
    creat(Tree,preorder,inorder,0)
    postorder(Tree)
    print('\r')