python3

javascript

java

Range Sum of BST

Given the `root` node of a binary search tree and two integers `low` and `high`, return *the sum of values of all nodes with a value in the **inclusive** range *[low, high]**.

```
Class TreeNode:
    val (int)
    left (TreeNode)
    right (TreeNode)
```

### Input Format:

First Parameter - TreeNode `root`

Second Parameter - Number `low`

Third Parameter - Number `high`

### Output Format:

Return the number.

### Example 1:
![img](https://devsnest-custom-images.s3.ap-south-1.amazonaws.com/range%20sum%20bst)

    Input:
        root = [10 5 15 3 7 null 18]
        low = 7
        high = 15
    Output:
        32

### Example 2:
![img](https://devsnest-custom-images.s3.ap-south-1.amazonaws.com/range%20sum%20bst%202)

    Input:
        root = [10 5 15 3 7 13 18 1 null 6]
        low = 6
        high = 10
    Output:
        23

#### Constraints:
+ The number of nodes in this range [1 , 2 * 10^4^]
+ 1 <= `node.val` <= 10^5^
+ 1 <=` low` <= `high` <= 10^5^
+ All `Node.val` are **unique**.
+ Expected Time Complexity: O(N)
+ Expected Space Complexity: O(N)


def solve(root, low, high):
    # CODE HERE

function solve(root, low, high){
// CODE HERE
}

int solve(TreeNode* root, int low, int high){
//CODE HERE 
}

static int solve(TreeNode root, int low, int high){
//CODE HERE 
}