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.
|
|
|
|
/**
|
|
|
|
|
* 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';
|
|
|
|
|
|
|
|
|
|
/* 层序遍历 */
|
|
|
|
|
List<int> levelOrder(TreeNode? root) {
|
|
|
|
|
// 初始化队列，加入根结点
|
|
|
|
|
Queue<TreeNode?> queue = Queue();
|
|
|
|
|
queue.add(root);
|
|
|
|
|
// 初始化一个列表，用于保存遍历序列
|
|
|
|
|
List<int> res = [];
|
|
|
|
|
while (queue.isNotEmpty) {
|
|
|
|
|
TreeNode? node = queue.removeFirst(); // 队列出队
|
|
|
|
|
res.add(node!.val); // 保存结点值
|
|
|
|
|
if (node.left != null) queue.add(node.left); // 左子结点入队
|
|
|
|
|
if (node.right != null) queue.add(node.right); // 右子结点入队
|
|
|
|
|
}
|
|
|
|
|
return res;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Driver Code */
|
|
|
|
|
void main() {
|
|
|
|
|
/* 初始化二叉树 */
|
|
|
|
|
// 这里借助了一个从数组直接生成二叉树的函数
|
|
|
|
|
TreeNode? root = listToTree([1, 2, 3, 4, 5, 6, 7]);
|
|
|
|
|
print("\n初始化二叉树\n");
|
|
|
|
|
printTree(root);
|
|
|
|
|
|
|
|
|
|
// 层序遍历
|
|
|
|
|
List<int> res = levelOrder(root);
|
|
|
|
|
print("\n层序遍历的结点打印序列 = $res");
|
|
|
|
|
}
|
