solves product of array except itself in java

Author: anishLearnsToCode

README.md

@@ -192,7 +192,7 @@
 | 235  | [Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree)                            |                 [![Java](assets/java.png)](src/LowestCommonAncestorOfBinarySearchTree.java) [![Python](assets/python.png)](python/lowest_common_ancestor_of_bst.py)                  |                                                                                                                                   |
 | 236  | [Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree)                                          |                                                        [![Java](assets/java.png)](src/LowestCommonAncestorOfBinaryTree.java)                                                         |                                                                                                                                   |
 | 237  | [Delete a Node In A Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list)                                                              |                          [![Java](assets/java.png)](src/DeleteANodeInLinkedList.java) [![Python](assets/python.png)](python/delete_node_in_linked_list.py)                           |                                                                                                                                   |
-| 238  | [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self)                                                                |                                                                                                                                                                                      |                                                                                                                                   |
+| 238  | [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self)                                                                |                                                           [![Java](assets/java.png)](src/ProductOfArrayExceptItself.java)                                                            |                                                                                                                                   |
 | 240  | [Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii)                                                                              |                                                                                                                                                                                      |                                                                                                                                   |
 | 241  | [Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses)                                                      |                                                                                                                                                                                      |                                                                                                                                   |
 | 242  | [Valid Anagram](https://leetcode.com/problems/valid-anagram)                                                                                              |                                [![Java](assets/java.png)](src/ValidAnagram.java) [![Python](assets/python.png)](python/delete_node_in_linked_list.py)                                |                                                                                                                                   |

src/ProductOfArrayExceptItself.java

@@ -4,34 +4,25 @@
 
 public class ProductOfArrayExceptItself {
 
-    private record ProductDetails(int nonZeroProduct, int numberOfZeros) { }
-
     public int[] productExceptSelf(int[] nums) {
-        final ProductDetails productDetails = getProductDetails(nums);
-        if (productDetails.numberOfZeros > 1) return new int[nums.length];
-        if (productDetails.numberOfZeros == 1) return productSumOnlyWhenZero(nums, productDetails.nonZeroProduct);
         final int[] result = new int[nums.length];
-        for (int i = 0 ; i < result.length ; i++) {
-            result[i] = productDetails.nonZeroProduct / nums[i];
-        }
+        multipleWithLeftPrefix(nums, result);
+        multiplyWithRightPostfix(nums, result);
         return result;
     }
 
-    private int[] productSumOnlyWhenZero(int[] array, int product) {
-        final int[] result = new int[array.length];
-        for (int i = 0 ; i < array.length ; i++) {
-            if (array[i] == 0) result[i] = product;
+    private void multipleWithLeftPrefix(int[] numbers, int[] result) {
+        result[0] = 1;
+        for(int i = 1 ; i < numbers.length ; i++) {
+            result[i] = result[i - 1] * numbers[i - 1];
         }
-        return result;
     }
 
-    private ProductDetails getProductDetails(int[] array) {
-        int numberOfZeros = 0;
-        int nonZeroProduct = 1;
-        for (int element : array) {
-            if (element == 0) numberOfZeros++;
-            else nonZeroProduct *= element;
+    private void multiplyWithRightPostfix(int[] numbers, int[] result) {
+        int right = 1;
+        for(int i = result.length - 1 ; i >= 0 ; i--) {
+            result[i] *= right;
+            right *= numbers[i];
         }
-        return new ProductDetails(nonZeroProduct, numberOfZeros);
     }
 }