ctci-linked-list-cycle.cpp

// Linked Lists: Detect a Cycle
// Given a pointer to the head of a linked list, determine whether the linked list loops back onto itself (i.e., determine if the list ends in a circularly linked list).
//
// https://www.hackerrank.com/challenges/ctci-linked-list-cycle/problem
//


#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
using namespace std;
struct Node
{
	int data;
	Node* next;
};


#include "ctci-linked-list-cycle.hpp"


int main()
{
	Node *A, *B, *C, *D,*E,*F;
	A = new Node();	B= new Node();  C= new Node(); D = new Node(); E = new Node(); F= new Node();
	// case 1:  NULL list
	if(has_cycle(NULL)) cout<<true<<endl;
	else cout<<false<<endl;
	//case 2:
	A->next = B;
	B->next = C;
	C->next = A;
	if(has_cycle(A)) cout<<true<<endl;
	else cout<<false<<endl;
	//case 3:
	A->next = B; B->next = C; C->next = D; D->next = E; E->next = F; F->next = E;
	if(has_cycle(A)) cout<<true<<endl;
	else cout<<false<<endl;
	//case 4:
	A->next = B; B->next = C; C->next = D; D->next = E; E->next = F; F->next = NULL;
	if(has_cycle(A)) cout<<true<<endl;
	else cout<<false<<endl;
	// case 5:
	A->next = B; B->next = C; C->next = D; D->next = E; E->next = F; F->next = A;
	if(has_cycle(A)) cout<<true<<endl;
	else cout<<false<<endl;
}