270_Closest_BST_Value

Leetcode 270: Closest Binary Search Tree Value
Detailed video explanation: https://youtu.be/lIKZB_rhFNM
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C++:
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class Solution {
public:
    int closestValue(TreeNode* root, double target) {
        if(root->val > target && root->left) {
            int l = closestValue(root->left, target);
            if(abs(l-target) < abs(root->val-target)) return l;
            return root->val;
        }
        if(root->val < target && root->right) {
            int r = closestValue(root->right, target);
            if(abs(r-target) < abs(root->val-target)) return r;
            return root->val;
        }
        return root->val;
    }
};


Java:
----
class Solution {
    public int closestValue(TreeNode root, double target) {
        if(root.val > target && root.left != null) {
            int l = closestValue(root.left, target);
            if(Math.abs(l-target) < Math.abs(root.val-target)) return l;
            return root.val;
        }
        if(root.val < target && root.right != null) {
            int r = closestValue(root.right, target);
            if(Math.abs(r-target) < Math.abs(root.val-target)) return r;
            return root.val;
        }
        return root.val;
    }
}


Python3:
-------
class Solution:
    def closestValue(self, root: TreeNode, target: float) -> int:
        if root.val > target and root.left != None: 
            l = self.closestValue(root.left, target)
            if abs(l-target) < abs(root.val-target): return l
            return root.val
        if root.val < target and root.right != None: 
            r = self.closestValue(root.right, target)
            if abs(r-target) < abs(root.val-target): return r
            return root.val
        return root.val