diff --git a/Design HashSet.py b/Design HashSet.py
new file mode 100644
index 00000000..858464fa
--- /dev/null
+++ b/Design HashSet.py	
@@ -0,0 +1,63 @@
+# Time Complexity: O(1) for add, remove, and contains
+# Space Complexity: O(1), because the maximum key range is fixed
+# Did this code successfully run on LeetCode: Yes
+
+class MyHashSet(object):
+
+    def __init__(self):
+        self.primaryBuckets = 1000
+        self.secondaryBuckets = 1000
+        self.storage = [None] * self.primaryBuckets
+
+    def getPrimaryHash(self, key):
+        return key % self.primaryBuckets
+
+    def getSecondaryHash(self, key):
+        return key // self.secondaryBuckets   
+        
+
+    def add(self, key):
+        """
+        :type key: int
+        :rtype: None
+        """
+        primaryHash = self.getPrimaryHash(key)
+        if self.storage[primaryHash] == None:
+            if primaryHash == 0:
+                self.storage[primaryHash] = [False] * (self.secondaryBuckets + 1)
+            else:
+                self.storage[primaryHash] = [False] * self.secondaryBuckets
+        secondaryHash = self.getSecondaryHash(key)
+        self.storage[primaryHash][secondaryHash] = True
+        
+
+    def remove(self, key):
+        """
+        :type key: int
+        :rtype: None
+        """
+        primaryHash = self.getPrimaryHash(key)
+        if self.storage[primaryHash] is None:
+            return
+        secondaryHash = self.getSecondaryHash(key)
+        self.storage[primaryHash][secondaryHash] = False
+        
+
+    def contains(self, key):
+        """
+        :type key: int
+        :rtype: bool
+        """
+        primaryHash = self.getPrimaryHash(key)
+        if self.storage[primaryHash] is None:
+            return False
+        secondaryHash = self.getSecondaryHash(key)
+        return self.storage[primaryHash][secondaryHash]
+
+
+# Your MyHashSet object will be instantiated and called as such:
+obj = MyHashSet()
+obj.add(1)
+obj.add(2)
+obj.remove(1)
+print(obj.contains(1))
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diff --git a/MinStack.py b/MinStack.py
new file mode 100644
index 00000000..92a5634f
--- /dev/null
+++ b/MinStack.py
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+# Time Complexity: O(1) for push, pop, top, and getMin
+# Space Complexity: O(n)
+
+# Did this code successfully run on LeetCode: Yes
+
+class MinStack(object):
+
+    def __init__(self):
+        self.st, self.minSt = [], []
+        self.min = float("inf") 
+        
+
+    def push(self, value):
+        """
+        :type value: int
+        :rtype: None
+        """
+        if value <= self.min:
+            self.minSt.append(self.min)
+            self.min = value
+        self.st.append(value)
+        
+        
+
+    def pop(self):
+        """
+        :rtype: None
+        """
+        if self.min == self.st.pop():
+            self.min = self.minSt.pop()
+        
+
+    def top(self):
+        """
+        :rtype: int
+        """
+        return self.st[-1]
+        
+
+    def getMin(self):
+        """
+        :rtype: int
+        """
+        return self.min
+        
+
+
+# Your MinStack object will be instantiated and called as such:
+obj = MinStack()
+obj.push(2)
+obj.push(1)
+obj.push(4)
+obj.pop()
+print(obj.top())
+print(obj.getMin())
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