Algorithm

Problem Name: 700. Search in a Binary Search Tree

Problem Link: https://leetcode.com/problems/search-in-a-binary-search-tree/


You are given the root of a binary search tree (BST) and an integer val.

Find the node in the BST that the node's value equals val and return the subtree rooted with that node. If such a node does not exist, return null.

 

Example 1:

Input: root = [4,2,7,1,3], val = 2
Output: [2,1,3]

Example 2:

Input: root = [4,2,7,1,3], val = 5
Output: []

 

Constraints:

  • The number of nodes in the tree is in the range [1, 5000].
  • 1 <= Node.val <= 107
  • root is a binary search tree.
  • 1 <= val <= 107
 

Code Examples

#1 Code Example with Java Programming

Code - Java Programming


class Solution {
  public TreeNode searchBST(TreeNode root, int val) {
    if (root == null) {
      return root;
    }
    if (root.val == val) {
      return root;
    }
    return root.val > val ? searchBST(root.left, val) : searchBST(root.right, val);
  }
}
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Input

x
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cmd
root = [4,2,7,1,3], val = 2

Output

x
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[2,1,3]

#2 Code Example with Javascript Programming

Code - Javascript Programming


const searchBST = function (root, val) {
  if (!root || root.val === val) {
    return root
  }
  return root.val < val ? searchBST(root.right, val) : searchBST(root.left, val)
}
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Input

x
–
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cmd
root = [4,2,7,1,3], val = 2

Output

x
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cmd
[2,1,3]

#3 Code Example with Python Programming

Code - Python Programming


class Solution:
    def searchBST(self, root, val):
        if root and val < root.val: return self.searchBST(root.left, val)
        elif root and val > root.val: return self.searchBST(root.right, val)
        return root
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Input

x
–
+
cmd
root = [4,2,7,1,3], val = 5

Output

x
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cmd
[]

#4 Code Example with C# Programming

Code - C# Programming


namespace LeetCode
{
    public class _0700_SearchInABinarySearchTree
    {
        public TreeNode SearchBST(TreeNode root, int val)
        {
            if (root == null) return null;

            if (root.val == val) return root;
            else if (root.val  <  val) return SearchBST(root.right, val);
            else return SearchBST(root.left, val);
        }
    }
}
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Input

x
–
+
cmd
root = [4,2,7,1,3], val = 5

Output

x
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cmd
[]
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Demonstration

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