add three solution related to binary

Author: Zhanganjin0520

README.md

@@ -62,6 +62,7 @@
 |717|[1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/) | |Easy|
 |714|[Best Time to Buy and Sell Stock with Transaction Fee](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-transaction-fee) | |Medium|
 |712|[Minimum ASCII  Sum for Two Strings](https://leetcode.com/problems/minimum-ascii--sum-for-two-strings/) | |Medium|
+|704|[Binary Search](https://leetcode.com/problems/binary-search/)| [Java](./algorithms/binarySearch/Solution.java)
 |695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island/) | |Medium|
 |687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path/) | |Easy|
 |684|[Redundant Connection](https://leetcode.com/problems/redundant-connection/) | |Medium|
@@ -214,7 +215,7 @@
 |229|[Majority Element II](https://leetcode.com/problems/majority-element-ii/) | |Medium|
 |228|[Summary Ranges](https://leetcode.com/problems/summary-ranges/)| |Easy|
 |227|[Basic Calculator II](https://leetcode.com/problems/basic-calculator-ii/)| |Medium|
-|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/)| |Easy|
+|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/)| [java](./algorithms/invertBinaryTree/Solution.java) |Easy|
 |225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/)| |Medium|
 |224|[Basic Calculator](https://leetcode.com/problems/basic-calculator/)| |Medium|
 |223|[Rectangle Area](https://leetcode.com/problems/rectangle-area/)| |Easy|
@@ -326,7 +327,7 @@
 |111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/)| [js](./algorithms/minimumDepthOfBinaryTree/minimumDepthOfBinaryTree.js) |Easy|
 |110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/)| [java](./algorithms/balancedBinaryTree/Solution.java) |Easy|
 |109|[Convert Sorted List to Binary Search Tree](https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/)| |Medium|
-|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)| |Medium|
+|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)| [Java](./algorithms/convertSortedArrayToBST/Solution.java) |Medium|
 |107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)| |Easy|
 |106|[Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/)| |Medium|
 |105|[Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)| |Medium|

algorithms/binarySearch/Solution.java

@@ -0,0 +1,17 @@
+class Solution {
+    public int search(int[] nums, int target) {
+        int left = 0;
+        int right = nums.length - 1;
+        while (left <= right) {
+            int mid = (left + right) / 2;
+            if (nums[mid] == target) {
+                return mid;
+            } else if (nums[mid] < target) {
+                left = mid + 1;
+            } else {
+                right = mid - 1;
+            }
+        }
+        return -1;
+    }
+}

algorithms/convertSortedArrayToBST/Solution.java

@@ -0,0 +1,28 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public TreeNode sortedArrayToBST(int[] nums) {
+        return helper(nums, 0, nums.length - 1);
+    }
+
+    public TreeNode helper(int[] nums, int left, int right) {
+        if (left > right) {
+            return null;
+        }
+
+        // 总是选择中间位置左边的数字作为根节点
+        int mid = (left + right) / 2;
+
+        TreeNode root = new TreeNode(nums[mid]);
+        root.left = helper(nums, left, mid - 1);
+        root.right = helper(nums, mid + 1, right);
+        return root;
+    }
+}

algorithms/invertBinaryTree/Solution.java

@@ -0,0 +1,21 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public TreeNode invertTree(TreeNode root) {
+        if (root == null) {
+            return null;
+        }
+        TreeNode left = invertTree(root.left);
+        TreeNode right = invertTree(root.right);
+        root.left = right;
+        root.right = left;
+        return root;
+    }
+}