Valid ParenthesesDaily Temperatures

Min Stack

medium

Time: O(1)

Space: O(n)

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

Constraints

pop, top, and getMin will always be called on non-empty stacks.

Examples

Input:

MinStack minStack = new MinStack(); minStack.Push(-2); minStack.Push(0); minStack.Push(-3); minStack.GetMin(); // return -3 minStack.Pop(); minStack.Top(); // return 0 minStack.GetMin(); // return -2

Output: null

Implement the MinStack class.