combination-sum solution

Author: hyeri0903

combination-sum/hyeri0903.java

@@ -0,0 +1,26 @@
+class Solution {
+    public List<List<Integer>> combinationSum(int[] candidates, int target) {
+        List<List<Integer>> answer = new ArrayList<>();
+        Arrays.sort(candidates); //불필요한 탐색을 줄이기 위해 sorting
+        dfs(0, candidates, target, new ArrayList<>(), answer);
+        return answer;
+        
+    }
+
+    public void dfs(int start, int[] candidates, int target, List<Integer> curList, List<List<Integer>> answer) {
+        if (target == 0) {
+            answer.add(new ArrayList<>(curList));
+            return;
+        }
+        for(int i = start; i < candidates.length; i++) {
+            if (candidates[i] > target) {
+                break;
+            }
+            
+            curList.add(candidates[i]);
+            dfs(i, candidates, target - candidates[i], curList, answer);
+            curList.remove(curList.size()-1); //다음 경우의 수를 위해 backtracking
+
+        }
+    }
+}