Merge pull request neetcode-gh#1228 from MaratKhakim/40-Comb-Sum-kt

Kotlin: 40. Combination Sum

kotlin/40-Combination-Sum.kt

@@ -0,0 +1,27 @@
+class Solution {
+    fun combinationSum2(candidates: IntArray, target: Int): List<List<Int>> {
+        val res = mutableListOf<List<Int>>()
+        candidates.sort()
+        dfs(candidates, target, 0, mutableListOf<Int>(), res)
+        return res
+    }
+
+    fun dfs(nums: IntArray, target: Int, idx: Int, list: MutableList<Int>, res: MutableList<List<Int>>) {
+
+        if (target == 0) {
+            res.add(ArrayList(list))
+            return
+        }
+
+        if (idx >= nums.size || target < 0)
+            return
+
+        for (i in idx..nums.size-1) {
+            if (i == idx || nums[i] != nums[i-1]) {
+                list.add(nums[i])
+                dfs(nums, target - nums[i], i+1, list, res)
+                list.removeAt(list.size-1)
+            }
+        }
+    }
+}