112. Path Sum

class Solution {
    fun hasPathSum(root: TreeNode?, targetSum: Int): Boolean {
        if (root == null) return false
        if (root.left == null && root.right == null) return targetSum == root.`val`

        val leafVal = targetSum - root.`val`
        return hasPathSum(root.left, leafVal) || hasPathSum(root.right, leafVal)
    }
}