Create 0047-permutations-ii.kt

Author: a93a

Diff for: kotlin/0047-permutations-ii.kt

@@ -0,0 +1,31 @@
+class Solution {
+    fun permuteUnique(nums: IntArray): List<List<Int>> {
+        val count = HashMap<Int, Int>()
+        val permut = LinkedList<Int>()
+        val res = LinkedList<LinkedList<Int>>()
+        
+        for (n in nums) count[n] = count.getOrDefault(n, 0) + 1
+
+        fun backtrack() {
+            if (permut.size == nums.size) {
+                res.add(LinkedList(permut))
+                return
+            }
+            
+            for (n in count.keys) {
+                if (count[n]!! > 0) {
+                    permut.addLast(n)
+                    count[n] = count[n]!! - 1
+
+                    backtrack()
+
+                    count[n] = count[n]!! + 1
+                    permut.removeLast()
+                }     
+            }
+        }
+
+        backtrack()
+        return res
+    }
+}