combination sum

Author: eunhwa99

combination-sum/eunhwa99.java

@@ -30,3 +30,25 @@ private void backtrack(int[] candidates, int target, int start, List<Integer> cu
         }
     }
 }
+
+class newSolution{
+    public List<List<Integer>> combinationSum(int[] candidates, int target) {
+        List<List<Integer>> result = new ArrayList<>();
+        backtrack(result, new ArrayList<>(), candidates, target, 0);
+        return result;
+    }
+
+    private void backtrack(List<List<Integer>> result, List<Integer> tempList, int[] candidates, int remain, int start) {
+        if (remain < 0) return;         // 넘치면 종료
+        if (remain == 0) {
+            result.add(new ArrayList<>(tempList)); // 정답 조합 발견
+            return;
+        }
+
+        for (int i = start; i < candidates.length; i++) {
+            tempList.add(candidates[i]); // 후보 추가
+            backtrack(result, tempList, candidates, remain - candidates[i], i); // **같은 수를 다시 사용할 수 있으므로 i**
+            tempList.removeLast(); // 백트래킹 (되돌리기)
+        }
+    }
+}