Given an integer array nums where the elements are sorted in ascending order, convert it to a
binary search tree.
Example 1:
Input: nums = [-10,-3,0,5,9] Output: [0,-3,9,-10,null,5] Explanation: [0,-10,5,null,-3,null,9] is also accepted:
Example 2:
Input: nums = [1,3] Output: [3,1] Explanation: [1,null,3] and [3,1] are both height-balanced BSTs.
Constraints:
1 <= nums.length <= 104-104 <= nums[i] <= 104nums is sorted in a strictly increasing order.
class Solution {
public TreeNode sortedArrayToBST(int[] nums) {
return helper(nums , 0 , nums.length-1 );
}
public TreeNode helper(int[] nums , int start , int end ){
if(start> end ){
return null;
}
int mid = (start + end )/2 ;
TreeNode root = new TreeNode(nums[mid]);
root.left = helper(nums , start , mid-1);
root.right = helper(nums , mid+1 , end );
return root ;
}
}
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