Hacker Rank - Day 18 : Queues and Stacks

                   Day 18 : Queues and Stacks

Solution In Java 8:

import java.io.*;
import java.util.*;

public class Solution {
    Queue <Character> queue = new LinkedList<>();
    Deque <Character> stack = new ArrayDeque<>();
   
    public void pushCharacter(char ch){
        stack.push(ch);
    }
    public void enqueueCharacter(char ch){
        queue.add(ch);
    }
    public char popCharacter(){
        return stack.pop();
    }
    public char dequeueCharacter(){
        return queue.remove();
    }
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String input = scan.nextLine();
        scan.close();

        // Convert input String to an array of characters:
        char[] s = input.toCharArray();

        // Create a Solution object:
        Solution p = new Solution();

        // Enqueue/Push all chars to their respective data structures:
        for (char c : s) {
            p.pushCharacter(c);
            p.enqueueCharacter(c);
        }

        // Pop/Dequeue the chars at the head of both data structures and compare them:
        boolean isPalindrome = true;
        for (int i = 0; i < s.length/2; i++) {
            if (p.popCharacter() != p.dequeueCharacter()) {
                isPalindrome = false;               
                break;
            }
        }

        //Finally, print whether string s is palindrome or not.
        System.out.println( "The word, " + input + ", is "
                           + ( (!isPalindrome) ? "not a palindrome." : "a palindrome." ) );
    }
}



Solution In Python 3: 

import sys

class Solution:

    def __init__(self):

        self.stack = []

        self.queue = []

    def pushCharacter(self , ch):

        self.stack.append(ch)

    def enqueueCharacter(self , ch):

        self.queue.append(ch)

    def popCharacter(self):

        return self.stack.pop()

    def dequeueCharacter(self):

        ch = self.queue[0]

        self.queue = self.queue[1:]

        return ch       

        

s=input()

obj=Solution()   

l=len(s)

for i in range(l):
    obj.pushCharacter(s[i])
    obj.enqueueCharacter(s[i])
    
isPalindrome=True

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.")