Design-1

design_hashset.py

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+# Implemented using double hashing
+# TC -> O(1)
+# SC -> O(10^6) or O(N)
+
+class MyHashSet:
+    def __init__(self):
+        self.num_buckets = 1000
+        self.buckets = [None] * self.num_buckets
+
+    def add(self, key: int) -> None:
+        first_hash = self.first_hash(key)
+        second_hash = self.second_hash(key)
+        if self.buckets[first_hash] == None:
+            if first_hash == 0:
+                self.buckets[first_hash] = [False] * (self.num_buckets + 1)
+            else:
+                self.buckets[first_hash] = [False] * self.num_buckets
+        self.buckets[first_hash][second_hash] = True
+        return
+    def remove(self, key: int) -> None:
+        first_hash = self.first_hash(key)
+        second_hash = self.second_hash(key)
+        if self.buckets[first_hash]:
+            self.buckets[first_hash][second_hash] = False
+        return
+    def contains(self, key: int) -> bool:
+        first_hash = self.first_hash(key)
+        second_hash = self.second_hash(key)
+        if self.buckets[first_hash]:
+            return self.buckets[first_hash][second_hash]
+        return False
+    def first_hash(self, key) -> int:
+        return key % self.num_buckets
+    def second_hash(self, key) -> int:
+        return key // self.num_buckets
+
+
+
+
+# Your MyHashSet object will be instantiated and called as such:
+# obj = MyHashSet()
+# obj.add(key)
+# obj.remove(key)
+# param_3 = obj.contains(key)

design_min_stack.py

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+# Use 2 stacks, one for the actual elements and the other to keep track of current min in the stack
+# TC -> O(1)
+# SC -> O(n) where n are the number of elemets to store in the stack
+
+class MinStack:
+    def __init__(self):
+        self.stack = []
+        self.min_stack = [float("inf")]
+
+    def push(self, value: int) -> None:
+        self.stack.append(value)
+        current_min = self.min_stack[-1]
+        self.min_stack.append(min(current_min, value))
+
+    def pop(self) -> None:
+        self.stack.pop()
+        self.min_stack.pop()
+
+    def top(self) -> int:
+        return self.stack[-1]
+
+    def getMin(self) -> int:
+        return self.min_stack[-1]
+
+
+
+# Your MinStack object will be instantiated and called as such:
+# obj = MinStack()
+# obj.push(value)
+# obj.pop()
+# param_3 = obj.top()
+# param_4 = obj.getMin()