add problem 238

Author: juchanei

src/main/java/io/github/juchanei/leetcodeJava/ProductOfArrayExceptSelf.java

@@ -0,0 +1,38 @@
+package io.github.juchanei.leetcodeJava;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ProductOfArrayExceptSelf {
+    public int[] productExceptSelf(int[] nums) {
+        int[] productsFromLeft = new int[nums.length];
+        productsFromLeft[0] = 1;
+        for (int i = 1; i < nums.length; i++) {
+            productsFromLeft[i] = productsFromLeft[i - 1] * nums[i - 1];
+        }
+
+        int[] productsFromRight = new int[nums.length];
+        productsFromRight[nums.length - 1] = 1;
+        for (int i = nums.length - 2; 0 <= i; i--) {
+            productsFromRight[i] = productsFromRight[i + 1] * nums[i + 1];
+        }
+
+        int[] ret = new int[nums.length];
+        for (int i = 0; i < nums.length; i++) {
+            ret[i] = productsFromLeft[i] * productsFromRight[i];
+        }
+
+        return ret;
+    }
+
+    public static class UnitTest {
+        private ProductOfArrayExceptSelf poes = new ProductOfArrayExceptSelf();
+
+        @Test()
+        public void example1() {
+            int[] input = { 1, 2, 3, 4 };
+            int[] output = { 24, 12, 8, 6 };
+            Assert.assertArrayEquals(output, poes.productExceptSelf(input));
+        }
+    }
+}