diff --git a/SubSets/step1.md b/SubSets/step1.md
new file mode 100644
index 0000000..e69de29
diff --git a/SubSets/step2.md b/SubSets/step2.md
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index 0000000..4fe8c62
--- /dev/null
+++ b/SubSets/step2.md
@@ -0,0 +1,19 @@
+```java
+// Time spend: 02:01
+class Solution {
+    public List<List<Integer>> subsets(int[] nums) {
+        List<List<Integer>> res = new ArrayList<>();
+        backtrack(res, new ArrayList<>(), nums, 0);
+        return res;
+    }
+
+    private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
+        res.add(new ArrayList<>(tempList));
+        for (int i = start; i < nums.length; i++) {
+            tempList.add(nums[i]);
+            backtrack(res, tempList, nums, i + 1);
+            tempList.remove(tempList.size() - 1);
+        }
+    }
+}
+```
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diff --git a/SubSets/step3.md b/SubSets/step3.md
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+++ b/SubSets/step3.md
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+```java
+// Time spend: 01:41
+class Solution {
+    public List<List<Integer>> subsets(int[] nums) {
+        List<List<Integer>> res = new ArrayList<>();
+        backtrack(res, new ArrayList<>(), nums, 0);
+        return res;
+    }
+
+    private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
+        res.add(new ArrayList<>(tempList));
+        for (int i = start; i < nums.length; i++) {
+            tempList.add(nums[i]);
+            backtrack(res, tempList, nums, i + 1);
+            tempList.remove(tempList.size() - 1);
+        }
+    }
+}
+```
+
+```java
+// Time spend: 01:51
+class Solution {
+    public List<List<Integer>> subsets(int[] nums) {
+        List<List<Integer>> res = new ArrayList<>();
+        backtrack(res, new ArrayList<>(), nums, 0);
+        return res;
+    }
+
+    private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
+        res.add(new ArrayList<>(tempList));
+        for (int i = start; i < nums.length; i++) {
+            tempList.add(nums[i]);
+            backtrack(res, tempList, nums, i + 1);
+            tempList.remove(tempList.size() - 1);
+        }
+    }
+}
+```
+
+```java
+// Time spend: 01:23
+class Solution {
+    public List<List<Integer>> subsets(int[] nums) {
+        List<List<Integer>> res = new ArrayList<>();
+        backtrack(res, new ArrayList<>(), nums, 0);
+        return res;
+    }
+
+    private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
+        res.add(new ArrayList<>(tempList));
+        for (int i = start; i < nums.length; i++) {
+            tempList.add(nums[i]);
+            backtrack(res, tempList, nums, i + 1);
+            tempList.remove(tempList.size() - 1);
+        }
+    }
+}
+```
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