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.")