原題

實現(xiàn)一個棧，可以使用除了棧之外的數(shù)據(jù)結構

樣例

push(1)
pop()
push(2)
top()  // return 2
pop()
isEmpty() // return true
push(3)
isEmpty() // return false

解題思路

• 使用python list實現(xiàn)stack數(shù)據(jù)結構

完整代碼

class Stack:
    # initialize your data structure here.
    def __init__(self):
        self.items = []

    # @param x, an integer, push a new item into the stack
    # @return nothing
    def push(self, x):
        # Write your code here
        self.items.append(x)

    # @return nothing, pop the top of the stack
    def pop(self):
        # Write your code here
        self.items.pop()

    # @return an integer, return the top of the stack
    def top(self):
        # Write your code here
        return self.items[-1]

    # @return a boolean, check the stack is empty or not.
    def isEmpty(self):
        # Write your code here
        return len(self.items) == 0