diff --git a/src/solution/Solution.java b/src/solution/Solution.java
index 3fa9525..e0df66c 100644
--- a/src/solution/Solution.java
+++ b/src/solution/Solution.java
@@ -175,8 +175,18 @@ public class Solution {
      */
     public static int removeDuplicates(int[] nums) {
         int i = 0;
-        int[] newNums = new int[nums.length];
-        Map<Integer,Integer> duplicates = new HashMap<>();
-
+        for (int j = 0; j < nums.length; j++) {
+            if (j == 0){
+                nums[i] = nums[j];
+                i++;
+                continue;
+            }
+            int preValue = nums[j - 1];
+            if (nums[j] != preValue){
+                nums[i] = nums[j];
+                i++;
+            }
+        }
+        return i;
     }
 }