MEDIUM/src/medium/CombinationSum.java

Author: fishercoder1534

MEDIUM/src/medium/CombinationSum.java

@@ -0,0 +1,38 @@
+package medium;
+
+import java.util.*;
+
+import utils.CommonUtils;
+
+public class CombinationSum {
+
+    public List<List<Integer>> combinationSum(int[] candidates, int target) {
+        List<List<Integer>> result = new ArrayList();
+        Arrays.sort(candidates);
+        helper(candidates, target, 0, new ArrayList(), result);
+        return result;
+    }
+    
+    private void helper(int[] candidates, int target, int startIndex, List<Integer> curr, List<List<Integer>> result){
+        if(target > 0){
+            for(int i = startIndex; i < candidates.length; i++){
+                curr.add(candidates[i]);
+                helper(candidates, target-candidates[i], i, curr, result);
+                curr.remove(curr.size()-1);
+            }
+        } else if(target == 0){
+            List<Integer> list = new ArrayList(curr);
+            result.add(list);
+        }
+    }
+
+    
+    public static void main(String...args){
+        CombinationSum test = new CombinationSum();
+        int[] candidates = new int[]{2,3,6,7};
+        int target = 7;
+        List<List<Integer>> result = test.combinationSum(candidates, target);
+        CommonUtils.printIntegerList(result);
+    }
+
+}