[LeetCode]Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

深搜+递归

思想：每次将数组中最中间的数作为根节点，然后递归

/** * Definition for binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public TreeNode sortedArrayToBST(int[] num) {        return sortedArrayToBST(num,0,num.length-1);    }        private TreeNode sortedArrayToBST(int []num,int start,int end){    if(start>end||num.length<1) return null;    int mid = (start+end)/2;    TreeNode tn = new TreeNode(num[mid]);    tn.left = sortedArrayToBST(num,start,mid-1);    tn.right = sortedArrayToBST(num,mid+1,end);    return tn;    }}