Merge pull request neetcode-gh#2936 from neetcode-gh/0039-combination-sum

Swift: 39. Combination Sum

Author: felivalencia3

swift/0039-combination-sum.swift

@@ -0,0 +1,23 @@
+class Solution {
+    func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]] {
+        var result: [[Int]] = []
+        var currentComb: [Int] = []
+        func dfs(_ index: Int, _ remaining: Int) {
+            guard index < candidates.count else { return }
+            guard remaining >= 0 else {
+                return
+            }
+            if remaining == 0 {
+                result.append(currentComb)
+                return
+            }
+            for i in index..<candidates.count {
+                currentComb.append(candidates[i])
+                dfs(i, remaining - candidates[i])
+                currentComb.removeLast()
+            }
+        }
+        dfs(0, target)
+        return result
+    }
+}