一 實現(xiàn)二叉樹的按層遍歷

1.1 描述

1）其實就是寬度優(yōu)先遍歷，用隊列

2）可以通過設置flag變量的方式，來發(fā)現(xiàn)某一層的結束（看題目）看下邊的第四題解答

1.2 代碼

public class Code01_LevelTraversalBT {public static class Node {public int value;public Node left;public Node right;public Node(int v) {value = v;}}public static void level(Node head) {if (head == null) {return;}Queue<Node> queue = new LinkedList<>();queue.add(head);while (!queue.isEmpty()) {Node cur = queue.poll();System.out.println(cur.value);if (cur.left != null) {queue.add(cur.left);}if (cur.right != null) {queue.add(cur.right);}}}