Stack Data Structure

Hello, in this article we're going to talk about stack;

Definition of Stack

"A stack is a linear data structure that stores items in a Last-In/First-Out (LIFO) or First-In/Last-Out (FILO) manner. In stack, a new element is added at one end and an element is removed from that end only. The insert and delete operations are often called push and pop."

www.geeksforgeeks.org

Space and Time complexity

the space complexity of a stack is O(n)

push	pop	peek
O(1)	O(1)	O(1)

implementation of a stack using list in python

class Stack :
    def __init__(self):
        self.items = []
        self.top = 0

    def push(self,data: any) -> any :
        self.items.append(data)
        self.top+=1
        return data

    def pop(self) -> any:
        if self.top > 0 :
            self.top -=1
            return self.items.pop()
    def peek(self) -> any:
        if self.top > 0:
            return self.items[-1]

    def __len__(self) -> int:
        return self.top

    def clear(self) -> list:
        self.items = []
        self.top = 0
        return self.items

    def isEmpty(self) -> bool:
        return self.items == []

    def printAll(self) -> list:
        return self.items

References and useful Ressources

thank you!
#day_2

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Aya Bouchiha

Definition of Stack

Space and Time complexity

implementation of a stack using list in python

References and useful Ressources

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