80 lines
2.1 KiB
Java
80 lines
2.1 KiB
Java
//给定一个二叉树，找出其最大深度。
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//
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// 二叉树的深度为根节点到最远叶子节点的最长路径上的节点数。
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//
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// 说明: 叶子节点是指没有子节点的节点。
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//
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// 示例：
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//给定二叉树 [3,9,20,null,null,15,7]，
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//
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// 3
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// / \
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// 9 20
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// / \
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// 15 7
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//
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// 返回它的最大深度 3 。
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// Related Topics 树 深度优先搜索 广度优先搜索 二叉树 👍 1012 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.TreeNode;
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import java.util.LinkedList;
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import java.util.Queue;
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//104:二叉树的最大深度
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class MaximumDepthOfBinaryTree {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new MaximumDepthOfBinaryTree().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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/**
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* Definition for a binary tree node.
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* public class TreeNode {
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* int val;
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* TreeNode left;
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* TreeNode right;
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* TreeNode() {}
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* TreeNode(int val) { this.val = val; }
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* TreeNode(int val, TreeNode left, TreeNode right) {
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* this.val = val;
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* this.left = left;
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* this.right = right;
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* }
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* }
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*/
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class Solution {
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public int maxDepth(TreeNode root) {
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if (root == null) {
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return 0;
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}
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Queue<TreeNode> queue = new LinkedList<>();
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queue.add(root);
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int count = 0;
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while (!queue.isEmpty()) {
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int size = queue.size();
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if (size > 0) {
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count++;
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}
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for (int i = 0; i < size; i++) {
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TreeNode node = queue.poll();
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assert node != null;
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if (node.left != null) {
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queue.add(node.left);
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}
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if (node.right != null) {
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queue.add(node.right);
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}
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}
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}
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return count;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |