61 lines
1.6 KiB
JavaScript
61 lines
1.6 KiB
JavaScript
/**
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* File: binary_tree_dfs.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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const { arrToTree } = require('../modules/TreeNode');
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const { printTree } = require('../modules/PrintUtil');
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// Initialize the list for storing traversal sequences
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const list = [];
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/* Pre-order traversal */
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function preOrder(root) {
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if (root === null) return;
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// Visit priority: root node -> left subtree -> right subtree
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list.push(root.val);
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preOrder(root.left);
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preOrder(root.right);
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}
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/* In-order traversal */
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function inOrder(root) {
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if (root === null) return;
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// Visit priority: left subtree -> root node -> right subtree
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inOrder(root.left);
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list.push(root.val);
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inOrder(root.right);
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}
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/* Post-order traversal */
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function postOrder(root) {
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if (root === null) return;
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// Visit priority: left subtree -> right subtree -> root node
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postOrder(root.left);
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postOrder(root.right);
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list.push(root.val);
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}
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/* Driver Code */
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/* Initialize binary tree */
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// Use a specific function to convert an array into a binary tree
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const root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
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console.log('\nInitialize binary tree\n');
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printTree(root);
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/* Pre-order traversal */
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list.length = 0;
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preOrder(root);
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console.log('\nPrint sequence of nodes from pre-order traversal = ' + list);
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/* In-order traversal */
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list.length = 0;
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inOrder(root);
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console.log('\nPrint sequence of nodes from in-order traversal = ' + list);
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/* Post-order traversal */
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list.length = 0;
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postOrder(root);
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console.log('\nPrint sequence of nodes from post-order traversal = ' + list);
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