Data Structure – codewindow.in

class MinStack:
    def __init__(self):
        self.stack = []
        self.min_stack = []

    def push(self, val):
        self.stack.append(val)
        if not self.min_stack or val <= self.min_stack[-1]:
            self.min_stack.append(val)

    def pop(self):
        if self.stack[-1] == self.min_stack[-1]:
            self.min_stack.pop()
        return self.stack.pop()

    def top(self):
        return self.stack[-1]

    def get_min(self):
        return self.min_stack[-1]