solves product of array except itself in java

Author: anishLearnsToCode

src/ProductOfArrayExceptItself.java

@@ -0,0 +1,37 @@
+// https://leetcode.com/problems/product-of-array-except-self
+// T: O(N)
+// S: O(1)
+
+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];
+        }
+        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;
+        }
+        return result;
+    }
+
+    private ProductDetails getProductDetails(int[] array) {
+        int numberOfZeros = 0;
+        int nonZeroProduct = 1;
+        for (int element : array) {
+            if (element == 0) numberOfZeros++;
+            else nonZeroProduct *= element;
+        }
+        return new ProductDetails(nonZeroProduct, numberOfZeros);
+    }
+}