CSC1001_3

class Node:
    def __init__(self, element, pointer):
        self.element=element
        self.pointer=pointer


class LinkedQueue:
    def __init__(self):
        self.head=None
        self.tail=None
        self.size=0

    def is_empty(self):
        return self.size==0

    def first(self):
        if self.is_empty:
            print("Queue is empty.")
        else:
            return self.head.element

    def dequeue(self):
        if self.is_empty():
            print("Queue is empty")
        else:
            answer=self.head.element
            self.head=self.head.pointer
            self.size-=1
            if self.is_empty():
                self.tail=None
            return answer

    def enqueue(self,e):
        newest=Node(e,None)
        if self.is_empty():
            self.head=newest
        else:
            self.tail.pointer=newest
        self.tail=newest
        self.size+=1

    def getItem(self, index):
        p = self.head
        count = 0
        while count != index:
            p = p.pointer
            count += 1
        return p.element

    def setItem(self, index, element):
        p = self.head
        count = -1
        while count < index-1:
            p = p.next
            count += 1
        p.element = element

    #swap
    def swapItem(self, i, j):
        t = self.getItem(j)
        self.setItem(j, self.getItem(i))
        self.setItem(i, t)




def quickSort(referance,left=0,right=q.size):
    global q
    #left=0
    #right=1
    #while referance.pointer!=None:
    #    referance=referance.pointer
     #   right+=1
    if left<right:
        i=left
        j=i+1
        start=q.getItem(i)
        while j<=right:
            while(j<=right and q.getItem(j)>=start):
                j+=1
            if j<=right:
                i+=1
                q.swapItem(i,j)
                j+=1
        q.swapItem(left,i)
        q.quickSort(q.getItem(left),left,i-1)
        q.quickSort(q.getItem(i+1), i+1, right)











q=LinkedQueue()
q.enqueue(3)
q.enqueue(5)
q.enqueue(1)
print(q.head.element)
#m=quickSort(q.head)
#print(m.head)