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61 lines
1.5 KiB
61 lines
1.5 KiB
/**
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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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// 初始化串列，用於儲存走訪序列
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const list = [];
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/* 前序走訪 */
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function preOrder(root) {
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if (root === null) return;
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// 訪問優先順序：根節點 -> 左子樹 -> 右子樹
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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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/* 中序走訪 */
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function inOrder(root) {
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if (root === null) return;
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// 訪問優先順序：左子樹 -> 根節點 -> 右子樹
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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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/* 後序走訪 */
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function postOrder(root) {
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if (root === null) return;
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// 訪問優先順序：左子樹 -> 右子樹 -> 根節點
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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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/* 初始化二元樹 */
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// 這裡藉助了一個從陣列直接生成二元樹的函式
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const root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
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console.log('\n初始化二元樹\n');
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printTree(root);
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/* 前序走訪 */
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list.length = 0;
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preOrder(root);
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console.log('\n前序走訪的節點列印序列 = ' + list);
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/* 中序走訪 */
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list.length = 0;
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inOrder(root);
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console.log('\n中序走訪的節點列印序列 = ' + list);
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/* 後序走訪 */
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list.length = 0;
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postOrder(root);
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console.log('\n後序走訪的節點列印序列 = ' + list);
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