108. 将有序数组转换为二叉搜索树 - 力扣(LeetCode)
找割点,一步一步将原数组分开。妙极了!!!!!
- /**
- * 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 sortedArrayToBST(int[] nums) {
- if(nums.length == 0) return null;
- int mid = nums.length/2;
- TreeNode t = new TreeNode(nums[mid]);
- t.left = sortedArrayToBST(Arrays.copyOfRange(nums,0,mid));
- t.right =sortedArrayToBST(Arrays.copyOfRange(nums,mid+1,nums.length));
- return t;
- }
- }