Refactor MinStack methods and documentation

Updated method names and docstrings for clarity.

Author: gokul000410

data_structures/stacks/min_stack.py

@@ -1,31 +1,32 @@
 """
 Description:
-Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
+Design a stack that supports push, pop, top, and retrieving the minimum element
+in constant time.
 
 Operations:
-1. push(x)   -> Push element x onto stack.
-2. pop()     -> Removes the element on top of the stack.
+1. push(x)   -> Push element x onto the stack.
+2. pop()     -> Removes the top element from the stack.
 3. top()     -> Get the top element.
-4. getMin()  -> Retrieve the minimum element in the stack.
+4. get_min() -> Retrieve the minimum element in the stack.
 
 Example:
     min_stack = MinStack()
     min_stack.push(-2)
     min_stack.push(0)
     min_stack.push(-3)
-    min_stack.getMin()  # returns -3
+    print(min_stack.get_min())  # Output: -3
     min_stack.pop()
-    min_stack.top()     # returns 0
-    min_stack.getMin()  # returns -2
+    print(min_stack.top())      # Output: 0
+    print(min_stack.get_min())  # Output: -2
 
 Time Complexity:
 - push: O(1)
 - pop: O(1)
 - top: O(1)
-- getMin: O(1)
+- get_min: O(1)
 
 Space Complexity:
-- O(n) extra space for the min_stack
+- O(n) extra space for the auxiliary stack
 """
 
 
@@ -36,56 +37,38 @@ def __init__(self):
         - main_stack: stores all elements
         - min_stack: stores the current minimum element at each level
         """
-        self.main_stack = []
-        self.min_stack = []
+        self.main_stack: list[int] = []
+        self.min_stack: list[int] = []
 
     def push(self, x: int) -> None:
-        """
-        Push element x onto stack.
-
-        Args:
-        x (int): Element to push
-        """
+        """Push element x onto stack."""
         self.main_stack.append(x)
-        # Push to min_stack if it's empty or x is <= current minimum
         if not self.min_stack or x <= self.min_stack[-1]:
             self.min_stack.append(x)
 
     def pop(self) -> None:
-        """
-        Removes the element on top of the stack.
-        """
+        """Remove the element on top of the stack."""
         if self.main_stack:
             val = self.main_stack.pop()
             if val == self.min_stack[-1]:
                 self.min_stack.pop()
 
-    def top(self) -> int:
-        """
-        Get the top element of the stack.
-
-        Returns:
-        int: Top element if stack is not empty, else None
-        """
+    def top(self) -> int | None:
+        """Get the top element of the stack."""
         return self.main_stack[-1] if self.main_stack else None
 
-    def getMin(self) -> int:
-        """
-        Retrieve the minimum element in the stack.
-
-        Returns:
-        int: Minimum element if stack is not empty, else None
-        """
+    def get_min(self) -> int | None:
+        """Retrieve the minimum element in the stack."""
         return self.min_stack[-1] if self.min_stack else None
 
 
-# Example Usage
+# Example usage
 if __name__ == "__main__":
     min_stack = MinStack()
     min_stack.push(-2)
     min_stack.push(0)
     min_stack.push(-3)
-    print("Current Min:", min_stack.getMin())  # Output: -3
+    print("Current Min:", min_stack.get_min())  # Output: -3
     min_stack.pop()
-    print("Top Element:", min_stack.top())  # Output: 0
-    print("Current Min:", min_stack.getMin())  # Output: -2
+    print("Top Element:", min_stack.top())      # Output: 0
+    print("Current Min:", min_stack.get_min())  # Output: -2