1 public class Solution {
 2     public TreeNode constructMaximumBinaryTree(int[] nums) {
 3         return construct(nums, 0, nums.length);
 4     }
 5     public TreeNode construct(int[] nums, int l, int r) {
 6         if (l == r)
 7             return null;
 8         int max_i = max(nums, l, r);
 9         TreeNode root = new TreeNode(nums[max_i]);
10         root.left = construct(nums, l, max_i);
11         root.right = construct(nums, max_i + 1, r);
12         return root;
13     }
14     public int max(int[] nums, int l, int r) {
15         int max_i = l;
16         for (int i = l; i < r; i++) {
17             if (nums[max_i] < nums[i])
18                 max_i = i;
19         }
20         return max_i;
21     }
22 }