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.
39 lines
1.0 KiB
39 lines
1.0 KiB
/**
|
|
* File: binary_tree_bfs.dart
|
|
* Created Time: 2023-04-03
|
|
* Author: liuyuxin (gvenusleo@gmai.com)
|
|
*/
|
|
|
|
import 'dart:collection';
|
|
import '../utils/print_util.dart';
|
|
import '../utils/tree_node.dart';
|
|
|
|
/* 層序走訪 */
|
|
List<int> levelOrder(TreeNode? root) {
|
|
// 初始化佇列，加入根節點
|
|
Queue<TreeNode?> queue = Queue();
|
|
queue.add(root);
|
|
// 初始化一個串列，用於儲存走訪序列
|
|
List<int> res = [];
|
|
while (queue.isNotEmpty) {
|
|
TreeNode? node = queue.removeFirst(); // 隊列出隊
|
|
res.add(node!.val); // 儲存節點值
|
|
if (node.left != null) queue.add(node.left); // 左子節點入列
|
|
if (node.right != null) queue.add(node.right); // 右子節點入列
|
|
}
|
|
return res;
|
|
}
|
|
|
|
/* 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);
|
|
|
|
// 層序走訪
|
|
List<int> res = levelOrder(root);
|
|
print("\n層序走訪的節點列印序列 = $res");
|
|
}
|