refactor 254

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_254.java

@@ -3,64 +3,30 @@
 import java.util.ArrayList;
 import java.util.List;
 
-/**
- * Numbers can be regarded as product of its factors. For example,
-
- 8 = 2 x 2 x 2;
- = 2 x 4.
- Write a function that takes an integer n and return all possible combinations of its factors.
-
- Note:
- You may assume that n is always positive.
- Factors should be greater than 1 and less than n.
- Examples:
- input: 1
- output:
- []
- input: 37
- output:
- []
- input: 12
- output:
- [
- [2, 6],
- [2, 2, 3],
- [3, 4]
- ]
- input: 32
- output:
- [
- [2, 16],
- [2, 2, 8],
- [2, 2, 2, 4],
- [2, 2, 2, 2, 2],
- [2, 4, 4],
- [4, 8]
- ]
- */
 public class _254 {
 
-    public List<List<Integer>> getFactors(int n) {
-        List<List<Integer>> result = new ArrayList<List<Integer>>();
-        helper(result, new ArrayList<Integer>(), n, 2);
-        return result;
-    }
+    public static class Solution1 {
+        public List<List<Integer>> getFactors(int n) {
+            List<List<Integer>> result = new ArrayList<>();
+            helper(result, new ArrayList<>(), n, 2);
+            return result;
+        }
 
-    public void helper(List<List<Integer>> result, List<Integer> item, int n, int start) {
-        if (n <= 1) {
-            if (item.size() > 1) {
-                result.add(new ArrayList<Integer>(item));
+        public void helper(List<List<Integer>> result, List<Integer> item, int n, int start) {
+            if (n <= 1) {
+                if (item.size() > 1) {
+                    result.add(new ArrayList<>(item));
+                }
+                return;
             }
-            return;
-        }
 
-        for (int i = start; i <= n; ++i) {
-            if (n % i == 0) {
-                item.add(i);
-                helper(result, item, n / i, i);
-                item.remove(item.size() - 1);
+            for (int i = start; i <= n; ++i) {
+                if (n % i == 0) {
+                    item.add(i);
+                    helper(result, item, n / i, i);
+                    item.remove(item.size() - 1);
+                }
             }
         }
     }
-
 }