solve problem Product Of Array Except Self

Author: P-ppc

README.md

@@ -298,6 +298,7 @@ All solutions will be accepted!
 |513|[Find Bottom Left Tree Value](https://leetcode-cn.com/problems/find-bottom-left-tree-value/description/)|[java/py/js](./algorithms/FindBottomLeftTreeValue)|Medium|
 |103|[Binary Tree Zigzag Level Order Traversal](https://leetcode-cn.com/problems/binary-tree-zigzag-level-order-traversal/description/)|[java/py/js](./algorithms/BinaryTreeZigzagLevelOrderTraversal)|Medium|
 |134|[Gas Station](https://leetcode-cn.com/problems/gas-station/description/)|[java/py/js](./algorithms/GasStation)|Medium|
+|238|[Product Of Array Except Self](https://leetcode-cn.com/problems/product-of-array-except-self/description/)|[java/py/js](./algorithms/ProductOfArrayExceptSelf)|Medium|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/ProductOfArrayExceptSelf/README.md

@@ -0,0 +1,2 @@
+# Product Of Array Except Self
+We can solve this problem by two array

algorithms/ProductOfArrayExceptSelf/Solution.java

@@ -0,0 +1,18 @@
+class Solution {
+    public int[] productExceptSelf(int[] nums) {
+        int length = nums.length;
+        int[] reverses = new int[length];
+    
+        for (int i = 0; i < length; i++)
+            reverses[length - 1 - i] = i == 0 ? nums[length - 1 - i] : nums[length - 1 - i] * reverses[length - i];
+        for (int i = 0; i < length; i++)
+            nums[i] = i == 0 ? nums[i] : nums[i] * nums[i - 1];
+
+        reverses[0] = reverses[1];
+        for (int i = 1; i < length - 1; i++)
+            reverses[i] = nums[i - 1] * reverses[i + 1];
+        reverses[length - 1] = nums[length - 2];
+
+        return reverses;
+    }
+}

algorithms/ProductOfArrayExceptSelf/solution.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var productExceptSelf = function(nums) {
+    let length = nums.length,
+        reverses = new Array(length)
+    
+    for (let i = 0; i < length; i++)
+        reverses[length - 1 - i] = i == 0 ? nums[length - 1 - i] : nums[length - 1 - i] * reverses[length - i]
+    for (let i = 0; i < length; i++)
+        nums[i] = i == 0 ? nums[i] : nums[i] * nums[i - 1]
+    
+    reverses[0] = reverses[1]
+    for (let i = 1; i < length - 1; i++)
+        reverses[i] = nums[i - 1] * reverses[i + 1]
+    reverses[length - 1] = nums[length - 2]
+    
+    return reverses
+};

algorithms/ProductOfArrayExceptSelf/solution.py

@@ -0,0 +1,20 @@
+class Solution(object):
+    def productExceptSelf(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[int]
+        """
+        length = len(nums)
+        reverse_products = [0] * length
+        
+        for i in xrange(length):
+            reverse_products[length - 1 - i] = nums[length - 1 - i] if i == 0 else nums[length - 1 - i] * reverse_products[length - i]
+        for i in xrange(length):
+            nums[i] = nums[i] if i == 0 else nums[i] * nums[i - 1]
+        
+        reverse_products[0] = reverse_products[1]
+        for i in xrange(1, length - 1):
+            reverse_products[i] = nums[i - 1] * reverse_products[i + 1]
+        reverse_products[-1] = nums[-2]
+        
+        return reverse_products