| ||
import data.structures.LinkedList.LinkedList; | ||
import data.structures.LinkedList.Node; | ||
/** | ||
* | ||
* @author jasleen | ||
* @param <T> | ||
*/ | ||
public class Stack<T> { | ||
final LinkedList<T> list; | ||
public Stack() { | ||
list=new LinkedList<>(); | ||
} | ||
public void push(T t) | ||
{ | ||
list.addAtHead(t); | ||
} | ||
public void pop() | ||
{ | ||
if(!isEmpty()) | ||
list.removeHead(); | ||
else | ||
System.out.println("There is no item to pop"); | ||
} | ||
public Node extractTop() | ||
{ | ||
Node t=list.head(); | ||
pop(); | ||
return t; | ||
} | ||
public T top() | ||
{ | ||
if(isEmpty()) | ||
{ | ||
System.out.println("There is no item"); | ||
return null; | ||
} | ||
return list.head().key(); | ||
} | ||
@Override | ||
public String toString() { | ||
StringBuilder builder=new StringBuilder(); | ||
builder.append("["); | ||
builder.append("\t"); | ||
Node currentTraversing=list.head(); | ||
while(currentTraversing!=null) | ||
{ | ||
builder.append(currentTraversing.key().toString()); | ||
builder.append("\t"); | ||
currentTraversing=currentTraversing.next(); | ||
} | ||
builder.append("]"); | ||
return builder.toString();//To change body of generated methods, choose Tools | Templates. | ||
} | ||
public boolean isEmpty() { | ||
return list.head()==null; //To change body of generated methods, choose Tools | Templates. | ||
} | ||
} |
Stack Implementation Java(Using Linked List)
Source code download here.
Check if given LinkedList is a pallindrome or not
Check if given LinkedList is a pallindrome or not
My version of the program. Open to corrections and improvements
/* | |
* To change this license header, choose License Headers in Project Properties. | |
* To change this template file, choose Tools | Templates | |
* and open the template in the editor. | |
*/ | |
package interview.practice; | |
import data.structures.LinkedList.LinkedList; | |
import data.structures.LinkedList.Node; | |
import data.structures.Stack.Stack; | |
/** | |
* | |
* @author jasleen | |
*/ | |
public class isPallindrome { | |
public static boolean isPallindrome(LinkedList list) { | |
Node single = list.head(), doubl = list.head(); | |
Stack stack = new Stack(); | |
if (single == null||single.next()==null) { | |
return false; | |
} | |
while (single.next() != null && doubl.next().next() != null) { | |
stack.push(single.key()); | |
single = single.next(); | |
doubl = doubl.next().next(); | |
if ( doubl.next() == null) { | |
break; | |
} | |
} | |
System.out.println(doubl); | |
System.out.println(single); | |
System.out.println(stack); | |
if (doubl.next()!= null) { | |
stack.push(single.key()); | |
single = single.next(); | |
Node popped=stack.extractTop(); | |
if (!single.key().toString().equals(popped.key().toString())) { | |
System.out.println("Returning at key" + popped.key().toString()+single.key()); | |
return false; | |
} | |
} | |
single = single.next(); | |
System.out.println(stack); | |
//System.out.println(single.key()); | |
while (single != null) { | |
Node popped=stack.extractTop(); | |
if (!single.key().toString().equals(popped.key().toString())) { | |
System.out.println("Returning at key" + popped.key().toString()+single.key()); | |
return false; | |
} | |
single = single.next(); | |
} | |
return true; | |
} | |
} |
Download code for this program here.
Download code for LinkedList here.
Download code for Node here.
Download code for Stack here.
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