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63 lines
1.4 KiB
63 lines
1.4 KiB
/**
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* File: binary_tree_dfs.dart
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* Created Time: 2023-04-04
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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import '../utils/print_util.dart';
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import '../utils/tree_node.dart';
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// 初始化列表，用于存储遍历序列
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List<int> list = [];
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/* 前序遍历 */
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void preOrder(TreeNode? node) {
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if (node == null) return;
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// 访问优先级：根节点 -> 左子树 -> 右子树
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list.add(node.val);
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preOrder(node.left);
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preOrder(node.right);
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}
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/* 中序遍历 */
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void inOrder(TreeNode? node) {
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if (node == null) return;
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// 访问优先级：左子树 -> 根节点 -> 右子树
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inOrder(node.left);
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list.add(node.val);
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inOrder(node.right);
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}
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/* 后序遍历 */
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void postOrder(TreeNode? node) {
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if (node == null) return;
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// 访问优先级：左子树 -> 右子树 -> 根节点
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postOrder(node.left);
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postOrder(node.right);
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list.add(node.val);
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}
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/* Driver Code */
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void main() {
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/* 初始化二叉树 */
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// 这里借助了一个从数组直接生成二叉树的函数
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TreeNode? root = listToTree([1, 2, 3, 4, 5, 6, 7]);
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print("\n初始化二叉树\n");
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printTree(root);
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/* 前序遍历 */
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list.clear();
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preOrder(root);
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print("\n前序遍历的节点打印序列 = $list");
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/* 中序遍历 */
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list.clear();
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inOrder(root);
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print("\n中序遍历的节点打印序列 = $list");
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/* 后序遍历 */
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list.clear();
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postOrder(root);
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print("\n后序遍历的节点打印序列 = $list");
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}
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