78. 子集

Author: w2xi

Diff for: README.md

@@ -45,6 +45,7 @@
 |71|[简化路径](https://leetcode.cn/problems/simplify-path/)|[JavaScript](./algorithms/simplify-path.js)|Medium|
 |73|[矩阵置零](https://leetcode.cn/problems/set-matrix-zeroes/)|[JavaScript](./algorithms/set-matrix-zeroes.js)|Medium|
 |77|[组合](https://leetcode.cn/problems/combinations/)|[JavaScript](./algorithms/combinations.js)|Medium|
+|78|[子集](https://leetcode.cn/problems/subsets/)|[JavaScript](./algorithms/subsets.js)|Medium|
 |82|[删除排序链表中的重复元素 II](https://leetcode.cn/problems/remove-duplicates-from-sorted-list-ii/)|[JavaScript](./algorithms/remove-duplicates-from-sorted-list-ii.js)|Medium|
 |83|[删除排序链表中的重复元素](https://leetcode.cn/problems/remove-duplicates-from-sorted-list/)|[JavaScript](./algorithms/remove-duplicates-from-sorted-list.js)|Easy|
 |88|[合并两个有序数组](https://leetcode.cn/problems/merge-sorted-array/)|[JavaScript](./algorithms/merge-sorted-array.js)|Easy|

Diff for: algorithms/subsets.js

@@ -0,0 +1,21 @@
+/**
+ * 78. 子集
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var subsets = function (nums) {
+  const result = [];
+  const path = [];
+
+  const backtracking = (nums, startIndex = 0) => {
+    result.push(path.slice());
+    for (let i = startIndex; i < nums.length; i++) {
+      path.push(nums[i]);
+      backtracking(nums, i + 1);
+      path.pop();
+    }
+  };
+  backtracking(nums);
+
+  return result;
+};