diff --git a/notes/3. 数组中重复的数字.md b/notes/3. 数组中重复的数字.md
index babab09d..4469fccf 100644
--- a/notes/3. 数组中重复的数字.md	
+++ b/notes/3. 数组中重复的数字.md	
@@ -36,7 +36,6 @@ public int duplicate(int[] nums) {
             }
             swap(nums, i, nums[i]);
         }
-        swap(nums, i, nums[i]);
     }
     return -1;
 }