diff --git a/design_hashset.py b/design_hashset.py
new file mode 100644
index 00000000..7f3c991d
--- /dev/null
+++ b/design_hashset.py
@@ -0,0 +1,46 @@
+class MyHashSet:
+
+
+
+  def __init__(self):
+    self.primary_buckets = 1000
+    self.secondary_buckets = 1001
+    self.storage = [None] * self.primary_buckets
+
+
+  def primary_hash(self, key)-> int:
+    return key % self.primary_buckets
+
+
+  def secondary_hash(self, key)-> int:
+    return key // self.secondary_buckets
+
+  def add(self, key)-> None:
+    primary_index = self.primary_hash(key)
+    secondary_index =self.secondary_hash(key)
+
+    if self.storage[primary_index]==None:
+      self.storage[primary_index] = [False] * self.secondary_buckets
+      self.storage[primary_index][secondary_index] = True
+
+    else:
+      self.storage[primary_index][secondary_index] = True
+
+  def remove(self, key) -> None:
+    primary_index = self.primary_hash(key)
+    secondary_index = self.secondary_hash(key)
+    if self.storage[primary_index]!=None:
+      self.storage[primary_index][secondary_index] = False
+
+
+  def contains(self, key) -> bool:
+    primary_index = self.primary_hash(key)
+    secondary_index = self.secondary_hash(key)
+    if self.storage[primary_index]!=None:
+      return self.storage[primary_index][secondary_index]==True
+    return False
+
+
+
+
+
diff --git a/design_minstack.py b/design_minstack.py
new file mode 100644
index 00000000..e9f5b08a
--- /dev/null
+++ b/design_minstack.py
@@ -0,0 +1,27 @@
+class MinStack:
+
+
+  def __init__(self):
+    self.stack =[]
+    self.min_stack =[]
+    self.min_val = float('inf')
+
+  def push(self,val)->None:
+    self.stack.append(val)
+    self.min_stack.append(val if val<self.min_val else self.min_val )
+    self.min_val = self.min_stack[-1]
+
+
+  def pop(self)->None:
+    self.stack.pop()
+    self.min_stack.pop()
+    self.min_val = self.min_stack[-1] if self.stack else float('inf')
+
+
+  def top(self)->int:
+    return self.stack[-1]
+
+  def getMin(self)->int:
+    return self.min_stack[-1]
+
+