496

Author: Amir-16

Easy/496. Next Greater Element I/solution.php

@@ -1,15 +1,43 @@
 <?php
-class Solution {
-
-    // /**
-    //  * @param Integer[] $nums1
-    //  * @param Integer[] $nums2
-    //  * @return Integer[]
-    //  */
-    function nextGreaterElement($nums1, $nums2) {
-        
+class Solution
+{
+    /**
+     * @param Integer[] $nums1
+     * @param Integer[] $nums2
+     * @return Integer[]
+     */
+    public function nextGreaterElement($nums1, $nums2)
+    {
+        $nextGreater = [];
+        $stack       = [];
+        $result      = [];
+
+        for ($i = count($nums2) - 1; $i >= 0; $i--) {
+
+            $number = $nums2[$i];
+
+            while (! empty($stack) && end($stack) <= $number) {
+                array_pop($stack);
+            }
+
+            $nextGreater[$number] = empty($stack) ? -1 : end($stack);
+
+            array_push($stack, $number);
+        }
+
+        return array_map(function($num) use ($nextGreater) {
+            return $nextGreater[$num];
+        }, $nums1);
+
     }
 }
 
+$solution = new Solution();
+
+$nums1 = [4, 1, 2, 7, 5, 3, 6];
+
+$nums2 = [1, 3, 4, 2, 7, 5, 6];
+
+$result = $solution->nextGreaterElement($nums1, $nums2);
 
-?>
+print_r($result); // Output: [7, 5, 6, 2, 4, 3, -1]