Merge branch 'master' of https://github.com/azl397985856/leetcode

Author: lucifer

problems/101.symmetric-tree.md

@@ -98,7 +98,84 @@ return True
 > 其实更像本题一点的话应该是从中间分别向两边扩展 😂
 
 ## 代码
+代码支持：C++, Java, Python3
+
+C++ Code:
+```c++
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    bool isSymmetric(TreeNode* root) {
+        return root==NULL?true:recur(root->left, root->right);
+    }
+
+    bool recur(TreeNode* l, TreeNode* r)
+    {
+        if(l == NULL && r==NULL)
+        {
+            return true;
+        }
+        // 只存在一个子节点 或者左右不相等 
+        if(l==NULL || r==NULL || l->val != r->val)
+        {
+            return false;
+        }
+
+        return recur(l->left, r->right) && recur(l->right, r->left);
+    }
+};
+```
+
+
+Java Code:
+```java
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public boolean isSymmetric(TreeNode root) {
+        if(root == null)
+        {
+            return true;
+        }
+        else{
+            return recur(root.left, root.right);
+        }
+        // return root == null ? true : recur(root.left, root.right);
+    }
+
+    public boolean recur(TreeNode l, TreeNode r)
+    {
+        if(l == null && r==null)
+        {
+            return true;
+        }
+        // 只存在一个子节点 或者左右不相等 
+        if(l==null || r==null || l.val != r.val)
+        {
+            return false;
+        }
+
+        return recur(l.left, r.right) && recur(l.right, r.left);
+    }
+}
+```
 
+Python3 Code:
 ```py
 
 class Solution:

problems/104.maximum-depth-of-binary-tree.md

@@ -64,7 +64,7 @@ var maxDepth = function (root) {
 
 ## 代码
 
-- 语言支持：JS，C++，Python
+- 语言支持：JS，C++，Java，Python
 
 JavaScript Code:
 
@@ -149,6 +149,55 @@ public:
 };
 ```
 
+Java Code:
+
+```java
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int maxDepth(TreeNode root) {
+        if(root == null)
+        {
+            return 0;
+        }
+        // 队列
+        Queue<TreeNode> queue = new LinkedList<TreeNode>();
+        queue.offer(root);
+        int res = 0;
+        // 按层扩展
+        while(!queue.isEmpty())
+        {
+            // 拿出该层所有节点，并压入子节点
+            int size = queue.size();
+            while(size > 0)
+            {
+                TreeNode node = queue.poll();
+
+                if(node.left != null)
+                {
+                    queue.offer(node.left);
+                }
+                if(node.right != null)
+                {
+                    queue.offer(node.right);
+                }
+                size-=1;
+            }
+            // 统计层数
+            res +=1;
+        }
+        return res;
+    }
+}
+```
+
 Python Code:
 
 ```python

problems/172.factorial-trailing-zeroes.md

@@ -57,7 +57,7 @@ https://leetcode-cn.com/problems/factorial-trailing-zeroes/
 
 ## 代码
 
-* 语言支持：JS，Python
+* 语言支持：JS，Python，C++, Java
 
 Javascript Code:
 
@@ -106,6 +106,41 @@ class Solution:
         return n // 5 + self.trailingZeroes(n // 5)
 ```
 
+C++ Code:
+
+```c++
+class Solution {
+public:
+    int trailingZeroes(int n) {
+        int res = 0;
+        while(n >= 5)
+        {
+            n/=5;
+            res += n;
+        }
+        return res;
+    }
+};
+```
+
+
+Java Code:
+
+```js
+class Solution {
+    public int trailingZeroes(int n) {
+        int res = 0;
+        while(n >= 5)
+        {
+            n/=5;
+            res += n;
+        }
+        return res;
+    }
+}
+```
+
+
 **复杂度分析**
 - 时间复杂度：$O(logN)$
 - 空间复杂度：$O(1)$

problems/219.contains-duplicate-ii.md

@@ -51,7 +51,7 @@ https://leetcode-cn.com/problems/contains-duplicate-ii/
 
 ## 代码
 
-* 语言支持：JS，Python，C++
+* 语言支持：JS，Python，C++, Java
 
 Javascript Code:
 
@@ -86,6 +86,7 @@ class Solution:
             d[num] = index
         return False
 ```
+
 C++ Code：
 ```C++
 class Solution {
@@ -106,6 +107,25 @@ public:
 };
 ```
 
+Java Code:
+
+```java
+class Solution {
+    public boolean containsNearbyDuplicate(int[] nums, int k) {
+        Map<Integer, Integer> map = new HashMap<>();
+        for(int i=0;i<nums.length;i++)
+        {
+            if(map.get(nums[i]) != null && (i-map.get(nums[i])) <= k)
+            {
+                return true;
+            }
+            map.put(nums[i], i);
+        }
+        return false;
+    }
+}
+```
+
 **复杂度分析**
 - 时间复杂度：$O(N)$
 - 空间复杂度：$O(N)$