package test.sachi.dsnalgos;
import java.util.NoSuchElementException;
import java.util.Stack;
/*
Create two stacks : 's' and 'tmps' as in the program given below
For insert operation :
if size of s = 0 then
push value into s
else
push all popped elements from s to tmps
push value into s
push all popped elements from tmps to s
For remove operation :
if size of s = 0 then
throw 'underflow' exception
else
return pop element from s
*/
public class QueueUsingTwoStacks {
Stack <Integer> s;
Stack <Integer> tmps;
public QueueUsingTwoStacks(){
s=new Stack<Integer>();
tmps=new Stack<Integer>();
}
public void insert(int data){
if(s.size()==0){
s.push(data);
}else{
int l=s.size();
for (int i = 0; i < l; i++){
tmps.push(s.pop());
}
s.push(data);
for (int i = 0; i < l; i++){
s.push(tmps.pop());
}
}
}
public int remove() throws Exception
{
if (s.size() == 0)
throw new NoSuchElementException("Underflow Exception");
return s.pop();
}
public int peek() throws Exception
{
if (s.size() == 0)
throw new NoSuchElementException("Underflow Exception");
return s.peek();
}
public boolean isEmpty()
{
return s.size() == 0 ;
}
public int getSize()
{
return s.size();
}
public void display()
{
System.out.print("\nQueue = ");
int l = getSize();
if (l == 0)
System.out.print("Empty\n");
else
{
for (int i = l - 1; i >= 0; i--)
System.out.print(s.get(i)+" ");
System.out.println();
}
}
}
