## PAT class a 1119 pre - and post order Traversals

PAT class a 1119 pre - and post order Traversals
Suppose that all the keys in a binary tree are distinct positive integers. A unique binary tree can be determined by a given pair of postorder and inorder traversal sequences, or preorder and inorder traversal sequences. However, if only the postorder and preorder traversal sequences are given, ...

Posted by **highjo** on *Sat, 04 Dec 2021 16:05:14 -0800*

## python: when for accesses the sequence, it modifies the sequence again and again. What's the problem

An instance
Take a basic topic: PAT (Basic Level) Practice 1005: continue 3n+1 to show this problem. For a detailed description of the topic, see the PAT website.
Problem solving ideas
1. After writing the input data, convert the sequence to be verified into the list num of digital elements_ list.
2. Traverse num from scratch_ List, for ea ...

Posted by **joelhop** on *Fri, 01 Oct 2021 15:34:29 -0700*