654.txt

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public TreeNode constructMaximumBinaryTree(int[] A) {
        return dfs(A,0,A.length-1);
    }
    
    public TreeNode dfs(int A[],int l,int r){
        if(l>r)return null;
        if(l==r)return new TreeNode(A[l]);
        int M=Integer.MIN_VALUE;
        int index=0;
        for(int i=l;i<=r;i++){
            if(A[i]>M){
                M=A[i];
                index=i;
            }
        }
        
        TreeNode node=new TreeNode(A[index]);
        node.left=dfs(A,l,index-1);
        node.right=dfs(A,index+1,r);
        
        return node;
        
    }
}