diff --git a/Jacklin/contains_duplicate.py b/Jacklin/contains_duplicate.py
new file mode 100644
index 0000000..eb20748
--- /dev/null
+++ b/Jacklin/contains_duplicate.py
@@ -0,0 +1,9 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        seen = set() 
+        for num in nums: 
+            if num in seen: 
+                return True 
+            else:
+                seen.add(num) 
+        return False 
\ No newline at end of file
diff --git a/Jacklin/groupanagram.py b/Jacklin/groupanagram.py
new file mode 100644
index 0000000..b487bcc
--- /dev/null
+++ b/Jacklin/groupanagram.py
@@ -0,0 +1,9 @@
+class Solution:
+    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
+        anagramGroups = defaultdict(list)
+        
+        for word in strs:
+            sortedWord = ''.join(sorted(word))  
+            anagramGroups[sortedWord].append(word) 
+        
+        return list(anagramGroups.values())
\ No newline at end of file
diff --git a/Jacklin/plusone.py b/Jacklin/plusone.py
new file mode 100644
index 0000000..1e9e835
--- /dev/null
+++ b/Jacklin/plusone.py
@@ -0,0 +1,9 @@
+class Solution:
+    def plusOne(self, digits: List[int]) -> List[int]:
+        n = len(digits) 
+        for i in range(n - 1, -1, -1): 
+            if digits[i] < 9: 
+                digits[i] += 1 
+                return digits
+            digits[i] = 0
+        return [1] + digits  
\ No newline at end of file
diff --git a/Jacklin/product_exceptself.py b/Jacklin/product_exceptself.py
new file mode 100644
index 0000000..89df424
--- /dev/null
+++ b/Jacklin/product_exceptself.py
@@ -0,0 +1,14 @@
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        n = len(nums)
+        answer = [1] * n
+        prefix = 1
+        for i in range(n):
+            answer[i] = prefix
+            prefix *= nums[i]
+        suffix = 1
+        for i in range(n - 1, -1, -1):
+            answer[i] *= suffix
+            suffix *= nums[i]
+
+        return answer
\ No newline at end of file
diff --git a/Jacklin/topk.py b/Jacklin/topk.py
new file mode 100644
index 0000000..e8a4a60
--- /dev/null
+++ b/Jacklin/topk.py
@@ -0,0 +1,15 @@
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        
+        frequency = Counter(nums)
+        buckets = [[] for _ in range(len(nums) + 1)]
+        
+        for num, freq in frequency.items():
+            buckets[freq].append(num)
+        
+        result = []
+        for i in range(len(buckets) - 1, 0, -1):
+            if buckets[i]:  
+                result.extend(buckets[i])
+                if len(result) >= k:  
+                    return result[:k]
diff --git a/Jacklin/twosum.py b/Jacklin/twosum.py
new file mode 100644
index 0000000..9e4ee6f
--- /dev/null
+++ b/Jacklin/twosum.py
@@ -0,0 +1,8 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        h = {} 
+        for i, n in enumerate(nums): 
+            c = target - n  
+            if c in h: 
+                return [h[c], i]
+            h[n] = i
diff --git a/Jacklin/validanagram.py b/Jacklin/validanagram.py
new file mode 100644
index 0000000..3c5c6dd
--- /dev/null
+++ b/Jacklin/validanagram.py
@@ -0,0 +1,5 @@
+class Solution:
+    def isAnagram(self, s: str, t: str) -> bool:
+        if len(s) != len(t):
+            return False
+        return Counter(s) == Counter(t)
\ No newline at end of file