30-queues-stacks.py

# Tutorials > 30 Days of Code > Day 18: Queues and Stacks
# Use stacks and queues to determine if a string is a palindrome.
#
# https://www.hackerrank.com/challenges/30-queues-stacks/problem
#

import sys
# (skeliton_head) ----------------------------------------------------------------------

class Solution:

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

    def pushCharacter(self, ch):
        self.stack.append(ch)

    def popCharacter(self):
        return self.stack.pop()

    def enqueueCharacter(self, ch):
        self.queue.append(ch)

    def dequeueCharacter(self):
        return self.queue.pop(0)

# (skeliton_tail) ----------------------------------------------------------------------
# read the string s
s=input()
#Create the Solution class object
obj=Solution()

l=len(s)
# push/enqueue all the characters of string s to stack
for i in range(l):
    obj.pushCharacter(s[i])
    obj.enqueueCharacter(s[i])

isPalindrome=True
'''
pop the top character from stack
dequeue the first character from queue
compare both the characters
'''
for i in range(l // 2):
    if obj.popCharacter()!=obj.dequeueCharacter():
        isPalindrome=False
        break
#finally print whether string s is palindrome or not.
if isPalindrome:
    print("The word, "+s+", is a palindrome.")
else:
    print("The word, "+s+", is not a palindrome.")