solve problem Maximum Binary Tree

Author: P-ppc

README.md

@@ -235,6 +235,7 @@ All solutions will be accepted!
 |60|[Permutation Sequence](https://leetcode-cn.com/problems/permutation-sequence/description/)|[java/py/js](./algorithms/PermutationSequence)|Medium|
 |106|[Construct Binary Tree From Inorder And Postorder Traversal](https://leetcode-cn.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/description/)|[java/py/js](./algorithms/ConstructBinaryTreeFromInorderAndPostorderTraversal)|Medium|
 |105|[Construct Binary Tree From Preorder And Inorder Traversal](https://leetcode-cn.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/description/)|[java/py/js](./algorithms/ConstructBinaryTreeFromPreorderAndInorderTraversal)|Medium|
+|654|[Maximum Binary Tree](https://leetcode-cn.com/problems/maximum-binary-tree/description/)|[java/py/js](./algorithms/MaximumBinaryTree)|Medium|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/MaximumBinaryTree/README.md

@@ -0,0 +1,2 @@
+# Maximum Binary Tree
+This problem is easy to solve by recursive

algorithms/MaximumBinaryTree/Solution.java

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+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public TreeNode constructMaximumBinaryTree(int[] nums) {
+        return build(nums, 0, nums.length - 1);
+    }
+    
+    public TreeNode build(int[] nums, int beg, int end) {
+        if (beg > end) return null;
+        
+        int maxIndex = beg;
+        for (int i = beg; i <= end; i++) {
+            if (nums[i] > nums[maxIndex]) maxIndex = i;
+        }
+        
+        TreeNode root = new TreeNode(nums[maxIndex]);
+        root.left = build(nums, beg, maxIndex - 1);
+        root.right = build(nums, maxIndex + 1, end);
+        return root;
+    }
+}

algorithms/MaximumBinaryTree/solution.js

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+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {number[]} nums
+ * @return {TreeNode}
+ */
+var constructMaximumBinaryTree = function(nums) {
+    return build(nums, 0, nums.length - 1)
+};
+
+var build = function(nums, beg, end) {
+    if (beg > end) return null
+    
+    let maxIndex = beg
+    for (let i = beg; i <= end; i++) {
+        if (nums[maxIndex] < nums[i]) {
+            maxIndex = i
+        }
+    }
+    
+    let root = new TreeNode(nums[maxIndex])
+    root.left = build(nums, beg, maxIndex - 1)
+    root.right = build(nums, maxIndex + 1, end)
+    return root
+};

algorithms/MaximumBinaryTree/solution.py

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+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def constructMaximumBinaryTree(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: TreeNode
+        """
+        return self.build(nums, 0, len(nums) - 1)
+    
+    def build(self, nums, beg, end):
+        if beg > end:
+            return None
+        
+        max_index = beg
+        for i in xrange(beg, end + 1):
+            if nums[i] > nums[max_index]:
+                max_index = i
+        
+        root = TreeNode(nums[max_index])
+        root.left = self.build(nums, beg, max_index - 1)
+        root.right = self.build(nums, max_index + 1, end)
+        return root