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.
43 lines
1.3 KiB
43 lines
1.3 KiB
/**
|
|
* File: binary_tree_bfs.java
|
|
* Created Time: 2022-11-25
|
|
* Author: krahets (krahets@163.com)
|
|
*/
|
|
|
|
package chapter_tree;
|
|
|
|
import utils.*;
|
|
import java.util.*;
|
|
|
|
public class binary_tree_bfs {
|
|
/* 層序走訪 */
|
|
static List<Integer> levelOrder(TreeNode root) {
|
|
// 初始化佇列，加入根節點
|
|
Queue<TreeNode> queue = new LinkedList<>();
|
|
queue.add(root);
|
|
// 初始化一個串列，用於儲存走訪序列
|
|
List<Integer> list = new ArrayList<>();
|
|
while (!queue.isEmpty()) {
|
|
TreeNode node = queue.poll(); // 隊列出隊
|
|
list.add(node.val); // 儲存節點值
|
|
if (node.left != null)
|
|
queue.offer(node.left); // 左子節點入列
|
|
if (node.right != null)
|
|
queue.offer(node.right); // 右子節點入列
|
|
}
|
|
return list;
|
|
}
|
|
|
|
public static void main(String[] args) {
|
|
/* 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 = TreeNode.listToTree(Arrays.asList(1, 2, 3, 4, 5, 6, 7));
|
|
System.out.println("\n初始化二元樹\n");
|
|
PrintUtil.printTree(root);
|
|
|
|
/* 層序走訪 */
|
|
List<Integer> list = levelOrder(root);
|
|
System.out.println("\n層序走訪的節點列印序列 = " + list);
|
|
}
|
|
}
|