#BST0000005. Ba kiểu duyệt và duyệt theo mức (Three DFS Traversals and Level Order)
Ba kiểu duyệt và duyệt theo mức (Three DFS Traversals and Level Order)
Three DFS Traversals and Level Order
Source: Phuoc Hung OJ
Version: Phuoc Hung OJ Extended
Problem Statement
Build a BST from in the given insertion order. Duplicate keys are ignored.
Print four traversals of the same resulting tree:
- preorder: root, left, right;
- inorder: left, root, right;
- postorder: left, right, root;
- level-order: visit nodes level by level from top to bottom; for each node, its left child is considered before its right child.
Input
The first line contains .
If , the next line contains signed integers . If , this line is absent.
Output
Print exactly four lines:
Line 1: preorder.
Line 2: inorder.
Line 3: postorder.
Line 4: level-order.
Keys on one line are separated by one space. If the tree is empty, all four lines must be EMPTY.
Subtasks
Subtask 1 (20 points): .
Subtask 2 (30 points): .
Subtask 3 (50 points): .
In all subtasks, . Duplicate keys are ignored.
Examples
Input
7
8 3 10 1 6 14 4
Output
8 3 1 6 4 10 14
1 3 4 6 8 10 14
1 4 6 3 14 10 8
8 3 10 1 6 14 4
Explanation
Key is the root, with and as its children. The four output lines are respectively the preorder, inorder, postorder, and level-order traversals of this same tree.