[Leetcode balanced binary tree C++] 108. Convert Sorted Array to Binary Search Tree

108. Convert Sorted Array to Binary Search Tree

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
    
    
public:
    TreeNode* sortedArrayToBST(int l, int r, vector<int>& nums) {
    
    
        if(l >= r) return nullptr;
        int mid = (l + r) / 2;
        TreeNode* root = new TreeNode(nums[mid]);
        root->left = sortedArrayToBST(l, mid, nums);
        root->right = sortedArrayToBST(mid+1, r, nums);
        return root;
    }
    TreeNode* sortedArrayToBST(vector<int>& nums) {
    
    
        return sortedArrayToBST(0, nums.size(), nums);
    }
};