Add search-in-a-binary-search-tree solution

Author: imajinyun

src/leetcode/SearchInABinarySearchTree.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace leetcode;
+
+use leetcode\util\TreeNode;
+
+class SearchInABinarySearchTree
+{
+    public static function searchBST(?TreeNode $root, int $val): ?TreeNode
+    {
+        if (!$root) {
+            return $root;
+        }
+
+        if ($root->val > $val) {
+            return self::searchBST($root->left, $val);
+        } elseif ($root->val < $val) {
+            return self::searchBST($root->right, $val);
+        } else {
+            return $root;
+        }
+    }
+
+    public static function searchBST2(?TreeNode $root, int $val): ?TreeNode
+    {
+        if (!$root) {
+            return $root;
+        }
+        $curr = $root;
+        while ($curr && $curr instanceof TreeNode) {
+            if ($curr->val > $val) {
+                $curr = $curr->left;
+            } elseif ($curr->val < $val) {
+                $curr = $curr->right;
+            } else {
+                return $curr;
+            }
+        }
+
+        return $curr;
+    }
+}

src/leetcode/util/TreeNode.php

@@ -30,7 +30,7 @@ public static function dfsTreeValues(TreeNode $tree, array &$list): void
 
     public static function bfsTreeValues(TreeNode $tree): array
     {
-        $ans = $items = $queue = [];
+        $ans = $queue = [];
         $queue = [$tree];
         while ($queue) {
             /** @var TreeNode $node */

tests/leetcode/SearchInABinarySearchTreeTest.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace leetcode\tests;
+
+use PHPUnit\Framework\TestCase;
+use leetcode\SearchInABinarySearchTree;
+use leetcode\util\TreeNode;
+
+class SearchInABinarySearchTreeTest extends TestCase
+{
+    private array $items;
+
+    protected function setUp(): void
+    {
+        $t1 = new TreeNode(4);
+        $t1->left = new TreeNode(2);
+        $t1->right = new TreeNode(7);
+        $t1->left->left = new TreeNode(1);
+        $t1->left->right = new TreeNode(3);
+
+        $t2 = clone $t1;
+
+        $this->items = [
+            [$t1, 2, [2, 1, 3]],
+            [$t2, 5, []],
+        ];
+    }
+
+    public function testSearchBST(): void
+    {
+        foreach ($this->items as $item) {
+            $node = SearchInABinarySearchTree::searchBST($item[0], $item[1]);
+            self::assertSame(
+                $item[2],
+                $node instanceof TreeNode ? TreeNode::bfsTreeValues($node) : []
+            );
+        }
+    }
+}