From b5a3282efb78ce0f9e2a88c3c457d154e15fd8ca Mon Sep 17 00:00:00 2001
From: Joshua <47053655+Joshua-Lu@users.noreply.github.com>
Date: Fri, 14 May 2021 01:21:36 +0800
Subject: [PATCH] =?UTF-8?q?Update=200111.=E4=BA=8C=E5=8F=89=E6=A0=91?=
 =?UTF-8?q?=E7=9A=84=E6=9C=80=E5=B0=8F=E6=B7=B1=E5=BA=A6.md?=
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添加 0111.二叉树的最小深度 Java版本
---
 problems/0111.二叉树的最小深度.md | 57 ++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/problems/0111.二叉树的最小深度.md b/problems/0111.二叉树的最小深度.md
index 6c6b4632..21cf36df 100644
--- a/problems/0111.二叉树的最小深度.md
+++ b/problems/0111.二叉树的最小深度.md
@@ -194,6 +194,61 @@ public:
 
 
 Java：
+```Java
+class Solution {
+    /**
+     * 递归法，相比求MaxDepth要复杂点
+     * 因为最小深度是从根节点到最近**叶子节点**的最短路径上的节点数量
+     */
+    public int minDepth(TreeNode root) {
+        if (root == null) {
+            return 0;
+        }
+        int leftDepth = minDepth(root.left);
+        int rightDepth = minDepth(root.right);
+        if (root.left == null) {
+            return rightDepth + 1;
+        }
+        if (root.right == null) {
+            return leftDepth + 1;
+        }
+        // 左右结点都不为null
+        return Math.min(leftDepth, rightDepth) + 1;
+    }
+}
+
+class Solution {
+   /**
+     * 迭代法，层序遍历
+     */
+    public int minDepth(TreeNode root) {
+        if (root == null) {
+            return 0;
+        }
+        Deque<TreeNode> deque = new LinkedList<>();
+        deque.offer(root);
+        int depth = 0;
+        while (!deque.isEmpty()) {
+            int size = deque.size();
+            depth++;
+            for (int i = 0; i < size; i++) {
+                TreeNode poll = deque.poll();
+                if (poll.left == null && poll.right == null) {
+                    // 是叶子结点，直接返回depth，因为从上往下遍历，所以该值就是最小值
+                    return depth;
+                }
+                if (poll.left != null) {
+                    deque.offer(poll.left);
+                }
+                if (poll.right != null) {
+                    deque.offer(poll.right);
+                }
+            }
+        }
+        return depth;
+    }
+}
+```
 
 Python：
 
@@ -250,4 +305,4 @@ Go：
 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
 * B站视频：[代码随想录](https://space.bilibili.com/525438321)
 * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
-<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>
\ No newline at end of file
+<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>