Add solution #90

Author: JoshCrozier

README.md

@@ -63,6 +63,7 @@
 78|[Subsets](./0078-subsets.js)|Medium|
 83|[Remove Duplicates from Sorted List](./0083-remove-duplicates-from-sorted-list.js)|Easy|
 88|[Merge Sorted Array](./0088-merge-sorted-array.js)|Easy|
+90|[Subsets II](./0090-subsets-ii.js)|Medium|
 94|[Binary Tree Inorder Traversal](./0094-binary-tree-inorder-traversal.js)|Easy|
 98|[Validate Binary Search Tree](./0098-validate-binary-search-tree.js)|Medium|
 100|[Same Tree](./0100-same-tree.js)|Easy|

solutions/0090-subsets-ii.js

@@ -0,0 +1,32 @@
+/**
+ * 90. Subsets II
+ * https://leetcode.com/problems/subsets-ii/
+ * Difficulty: Medium
+ *
+ * Given an integer array nums that may contain duplicates, return all possible subsets (the power set).
+ *
+ * The solution set must not contain duplicate subsets. Return the solution in any order.
+ */
+
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var subsetsWithDup = function(nums) {
+  const seen = new Set();
+  const result = [];
+  dfs([], 0);
+
+  function dfs(subset, start) {
+    const key = subset.sort((a, b) => a - b).join('');
+    if (!seen.has(key)) {
+      result.push(subset);
+      seen.add(key);
+    }
+    for (let index = start; index < nums.length; index++) {
+      dfs([...subset, nums[index]], index + 1);
+    }
+  }
+
+  return result;
+};