155. Min Stack

155. Min Stack

 

class MinStack:

    def __init__(self):
        self.min_value = []
        self.stack = []


    def push(self, val: int) -> None:
        self.stack.append(val)

        if len(self.min_value) == 0:
            self.min_value.append(val)
        else:
            self.min_value.append(min(self.min_value[-1], val))

    def pop(self) -> None:
        self.stack.pop()        
        self.min_value.pop()        

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

    def getMin(self) -> int:
        return self.min_value[-1]


# Your MinStack object will be instantiated and called as such:
# obj = MinStack()
# obj.push(val)
# obj.pop()
# param_3 = obj.top()
# param_4 = obj.getMin()

 

 

https://youtu.be/qkLl7nAwDPo?si=NAkNePjmgVyQa2ny

 

최종 코드

 

class MinStack:

    def __init__(self):
        self.val = []
        self.minimum = []        

    def push(self, val: int) -> None:
        if not self.minimum:
            self.minimum.append(val)
        else:
            if val < self.minimum[-1]:
                self.minimum.append(val)
            else:
                self.minimum.append(self.minimum[-1])

        self.val.append(val)

    def pop(self) -> None:
        self.val.pop()
        self.minimum.pop()        

    def top(self) -> int:
        return self.val[-1]

    def getMin(self) -> int:
        return self.minimum[-1]


# Your MinStack object will be instantiated and called as such:
# obj = MinStack()
# obj.push(val)
# obj.pop()
# param_3 = obj.top()
# param_4 = obj.getMin()