Kotlin: 90. Subsets II

Author: MaratKhakim

Diff for: kotlin/90-Subsets-II.kt

@@ -0,0 +1,21 @@
+class Solution {
+    fun subsetsWithDup(nums: IntArray): List<List<Int>> {
+        val res = mutableListOf<List<Int>>()
+        Arrays.sort(nums)
+        subsets(nums, 0, mutableListOf<Int>(), mutableSetOf<List<Int>>(), res)
+        return res
+    }
+
+    fun subsets(nums: IntArray, idx: Int, list: MutableList<Int>, set: MutableSet<List<Int>>, res: MutableList<List<Int>>) {
+        val copy = ArrayList(list)
+
+        if (set.add(copy))
+            res.add(copy)
+
+        for (i in idx..nums.size-1) {
+            list.add(nums[i])
+            subsets(nums, i+1, list, set, res)
+            list.removeAt(list.size-1)
+        }
+    }
+}