You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
63 lines
1.4 KiB
63 lines
1.4 KiB
/**
|
|
* File: binary_tree_dfs.dart
|
|
* Created Time: 2023-04-04
|
|
* Author: liuyuxin (gvenusleo@gmail.com)
|
|
*/
|
|
|
|
import '../utils/print_util.dart';
|
|
import '../utils/tree_node.dart';
|
|
|
|
// 初始化串列，用於儲存走訪序列
|
|
List<int> list = [];
|
|
|
|
/* 前序走訪 */
|
|
void preOrder(TreeNode? node) {
|
|
if (node == null) return;
|
|
// 訪問優先順序：根節點 -> 左子樹 -> 右子樹
|
|
list.add(node.val);
|
|
preOrder(node.left);
|
|
preOrder(node.right);
|
|
}
|
|
|
|
/* 中序走訪 */
|
|
void inOrder(TreeNode? node) {
|
|
if (node == null) return;
|
|
// 訪問優先順序：左子樹 -> 根節點 -> 右子樹
|
|
inOrder(node.left);
|
|
list.add(node.val);
|
|
inOrder(node.right);
|
|
}
|
|
|
|
/* 後序走訪 */
|
|
void postOrder(TreeNode? node) {
|
|
if (node == null) return;
|
|
// 訪問優先順序：左子樹 -> 右子樹 -> 根節點
|
|
postOrder(node.left);
|
|
postOrder(node.right);
|
|
list.add(node.val);
|
|
}
|
|
|
|
/* Driver Code */
|
|
void main() {
|
|
/* 初始化二元樹 */
|
|
// 這裡藉助了一個從陣列直接生成二元樹的函式
|
|
TreeNode? root = listToTree([1, 2, 3, 4, 5, 6, 7]);
|
|
print("\n初始化二元樹\n");
|
|
printTree(root);
|
|
|
|
/* 前序走訪 */
|
|
list.clear();
|
|
preOrder(root);
|
|
print("\n前序走訪的節點列印序列 = $list");
|
|
|
|
/* 中序走訪 */
|
|
list.clear();
|
|
inOrder(root);
|
|
print("\n中序走訪的節點列印序列 = $list");
|
|
|
|
/* 後序走訪 */
|
|
list.clear();
|
|
postOrder(root);
|
|
print("\n後序走訪的節點列印序列 = $list");
|
|
}
|