238. 除自身以外数组的乘积

Author: w2xi

README.md

@@ -113,6 +113,7 @@
 |235|[二叉搜索树的最近公共祖先](https://leetcode.cn/problems/lowest-common-ancestor-of-a-binary-search-tree/)|[JavaScript](./algorithms/lowest-common-ancestor-of-a-binary-search-tree.js)|Easy|
 |236|[二叉树的最近公共祖先](https://leetcode.cn/problems/lowest-common-ancestor-of-a-binary-tree/)|[JavaScript](./algorithms/lowest-common-ancestor-of-a-binary-tree.js)|Medium|
 |237|[删除链表中的节点](https://leetcode-cn.com/problems/delete-node-in-a-linked-list/)|[JavaScript](./algorithms/delete-node-in-a-linked-list.js)|Easy|
+|238|[除自身以外数组的乘积](https://leetcode.cn/problems/product-of-array-except-self/)|[JavaScript](./algorithms/product-of-array-except-self.js)|Medium|
 |239|[滑动窗口最大值](https://leetcode.cn/problems/sliding-window-maximum/)|[JavaScript](./algorithms/sliding-window-maximum.js)|Hard|
 |242|[有效的字母异位词](https://leetcode.cn/problems/valid-anagram/)|[JavaScript](./algorithms/valid-anagram.js)|Easy|
 |257|[二叉树的所有路径](https://leetcode.cn/problems/binary-tree-paths/)|[JavaScript](./algorithms/binary-tree-paths.js)|Easy|

algorithms/product-of-array-except-self.js

@@ -0,0 +1,21 @@
+/**
+ * 238. 除自身以外数组的乘积
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var productExceptSelf = function (nums) {
+  let result = Array(nums.length).fill(1);
+  let left = 1; // 从左边累乘
+  let right = 1; // 从右边累乘
+  let n = nums.length;
+
+  for (let i = 0; i < nums.length; i++) {
+    result[i] *= left; // 乘以其左边的乘积
+    left *= nums[i];
+
+    result[n - 1 - i] *= right; // 乘以其右边的乘积 
+    right *= nums[n - 1 - i];
+  }
+
+  return result;
+};