Escriba una función detectAndCountLoop() que verifique si una lista enlazada dada contiene un bucle y, si el bucle está presente, devuelve el recuento de Nodes en el bucle. Por ejemplo, el bucle está presente en la lista de enlaces a continuación y la longitud del bucle es 4. Si el bucle no está presente, la función debería devolver 0.
C++
// C++ program to count number of nodes
// in loop in a linked list if loop is
// present
#include<bits/stdc++.h>
using namespace std;
/* Link list node */
struct Node
{
int data;
struct Node* next;
};
// Returns count of nodes present in loop.
int countNodes(struct Node *n)
{
int res = 1;
struct Node *temp = n;
while (temp->next != n)
{
res++;
temp = temp->next;
}
return res;
}
/* This function detects and counts loop
nodes in the list. If loop is not there
in then returns 0 */
int countNodesinLoop(struct Node *list)
{
struct Node *slow_p = list, *fast_p = list;
while (slow_p && fast_p &&
fast_p->next)
{
slow_p = slow_p->next;
fast_p = fast_p->next->next;
/* If slow_p and fast_p meet at
some point then there is a loop */
if (slow_p == fast_p)
return countNodes(slow_p);
}
/* Return 0 to indicate that
there is no loop*/
return 0;
}
struct Node *newNode(int key)
{
struct Node *temp =
(struct Node*)malloc(sizeof(struct Node));
temp->data = key;
temp->next = NULL;
return temp;
}
// Driver Code
int main()
{
struct Node *head = newNode(1);
head->next = newNode(2);
head->next->next = newNode(3);
head->next->next->next = newNode(4);
head->next->next->next->next = newNode(5);
/* Create a loop for testing */
head->next->next->next->next->next = head->next;
cout << countNodesinLoop(head) << endl;
return 0;
}
// This code is contributed by SHUBHAMSINGH10
C
// C program to count number of nodes
// in loop in a linked list if loop is
// present
#include<stdio.h>
#include<stdlib.h>
/* Link list node */
struct Node
{
int data;
struct Node* next;
};
// Returns count of nodes present in loop.
int countNodes(struct Node *n)
{
int res = 1;
struct Node *temp = n;
while (temp->next != n)
{
res++;
temp = temp->next;
}
return res;
}
/* This function detects and counts loop
nodes in the list. If loop is not there
in then returns 0 */
int countNodesinLoop(struct Node *list)
{
struct Node *slow_p = list, *fast_p = list;
while (slow_p && fast_p && fast_p->next)
{
slow_p = slow_p->next;
fast_p = fast_p->next->next;
/* If slow_p and fast_p meet at some point
then there is a loop */
if (slow_p == fast_p)
return countNodes(slow_p);
}
/* Return 0 to indicate that there is no loop*/
return 0;
}
struct Node *newNode(int key)
{
struct Node *temp =
(struct Node*)malloc(sizeof(struct Node));
temp->data = key;
temp->next = NULL;
return temp;
}
/* Driver program to test above function*/
int main()
{
struct Node *head = newNode(1);
head->next = newNode(2);
head->next->next = newNode(3);
head->next->next->next = newNode(4);
head->next->next->next->next = newNode(5);
/* Create a loop for testing */
head->next->next->next->next->next = head->next;
printf("%d \n", countNodesinLoop(head));
return 0;
}
Java
// Java program to count number of nodes
// in loop in a linked list if loop is
// present
import java.io.*;
class GFG {
/* Link list node */
static class Node
{
int data;
Node next;
Node(int data)
{
this.data =data;
next =null;
}
}
// Returns count of nodes present in loop.
static int countNodes( Node n)
{
int res = 1;
Node temp = n;
while (temp.next != n)
{
res++;
temp = temp.next;
}
return res;
}
/* This function detects and counts loop
nodes in the list. If loop is not there
in then returns 0 */
static int countNodesinLoop( Node list)
{
Node slow_p = list, fast_p = list;
while (slow_p !=null && fast_p!=null && fast_p.next!=null)
{
slow_p = slow_p.next;
fast_p = fast_p.next.next;
/* If slow_p and fast_p meet at some point
then there is a loop */
if (slow_p == fast_p)
return countNodes(slow_p);
}
/* Return 0 to indicate that there is no loop*/
return 0;
}
static Node newNode(int key)
{
Node temp = new Node(key);
return temp;
}
/* Driver program to test above function*/
public static void main (String[] args) {
Node head = newNode(1);
head.next = newNode(2);
head.next.next = newNode(3);
head.next.next.next = newNode(4);
head.next.next.next.next = newNode(5);
/* Create a loop for testing */
head.next.next.next.next.next = head.next;
System.out.println( countNodesinLoop(head));
}
}
// This code is contributed by inder_verma.
Python3
# Python 3 program to find the number
# of nodes in loop in a linked list
# if loop is present
# Python Code to detect a loop and
# find the length of the loop
# Node defining class
class Node:
# Function to make a node
def __init__(self, val):
self.val = val
self.next = None
# Linked List defining and loop
# length finding class
class LinkedList:
# Function to initialize the
# head of the linked list
def __init__(self):
self.head = None
# Function to insert a new
# node at the end
def AddNode(self, val):
if self.head is None:
self.head = Node(val)
else:
curr = self.head
while(curr.next):
curr = curr.next
curr.next = Node(val)
# Function to create a loop in the
# Linked List. This function creates
# a loop by connecting the last node
# to n^th node of the linked list,
# (counting first node as 1)
def CreateLoop(self, n):
# LoopNode is the connecting node to
# the last node of linked list
LoopNode = self.head
for _ in range(1, n):
LoopNode = LoopNode.next
# end is the last node of the Linked List
end = self.head
while(end.next):
end = end.next
# Creating the loop
end.next = LoopNode
# Function to detect the loop and return
# the length of the loop if the returned
# value is zero, that means that either
# the linked list is empty or the linked
# list doesn't have any loop
def detectLoop(self):
# if linked list is empty then there
# is no loop, so return 0
if self.head is None:
return 0
# Using Floyd’s Cycle-Finding
# Algorithm/ Slow-Fast Pointer Method
slow = self.head
fast = self.head
flag = 0 # to show that both slow and fast
# are at start of the Linked List
while(slow and slow.next and fast and
fast.next and fast.next.next):
if slow == fast and flag != 0:
# Means loop is confirmed in the
# Linked List. Now slow and fast
# are both at the same node which
# is part of the loop
count = 1
slow = slow.next
while(slow != fast):
slow = slow.next
count += 1
return count
slow = slow.next
fast = fast.next.next
flag = 1
return 0 # No loop
# Setting up the code
# Making a Linked List and adding the nodes
myLL = LinkedList()
myLL.AddNode(1)
myLL.AddNode(2)
myLL.AddNode(3)
myLL.AddNode(4)
myLL.AddNode(5)
# Creating a loop in the linked List
# Loop is created by connecting the
# last node of linked list to n^th node
# 1<= n <= len(LinkedList)
myLL.CreateLoop(2)
# Checking for Loop in the Linked List
# and printing the length of the loop
loopLength = myLL.detectLoop()
if myLL.head is None:
print("Linked list is empty")
else:
print(str(loopLength))
# This code is contributed by _Ashutosh
C#
// C# program to count number of nodes
// in loop in a linked list if loop is
// present
using System;
class GFG
{
/* Link list node */
class Node
{
public int data;
public Node next;
public Node(int data)
{
this.data = data;
next = null;
}
}
// Returns count of nodes present in loop.
static int countNodes( Node n)
{
int res = 1;
Node temp = n;
while (temp.next != n)
{
res++;
temp = temp.next;
}
return res;
}
/* This function detects and counts loop
nodes in the list. If loop is not there
in then returns 0 */
static int countNodesinLoop( Node list)
{
Node slow_p = list, fast_p = list;
while (slow_p != null && fast_p != null &&
fast_p.next != null)
{
slow_p = slow_p.next;
fast_p = fast_p.next.next;
/* If slow_p and fast_p meet at some point
then there is a loop */
if (slow_p == fast_p)
return countNodes(slow_p);
}
/* Return 0 to indicate that there is no loop*/
return 0;
}
static Node newNode(int key)
{
Node temp = new Node(key);
return temp;
}
/* Driver code*/
public static void Main (String[] args)
{
Node head = newNode(1);
head.next = newNode(2);
head.next.next = newNode(3);
head.next.next.next = newNode(4);
head.next.next.next.next = newNode(5);
/* Create a loop for testing */
head.next.next.next.next.next = head.next;
Console.WriteLine( countNodesinLoop(head));
}
}
// This code is contributed by Rajput-Ji
Javascript
<script>
// javascript program to count number of nodes
// in loop in a linked list if loop is
// present
/* Link list node */
class Node {
constructor(data) {
this.data = data;
this.next = null;
}
}
// Returns count of nodes present in loop.
function countNodes( n) {
var res = 1;
temp = n;
while (temp.next != n) {
res++;
temp = temp.next;
}
return res;
}
/*
* This function detects and counts loop nodes in the list. If loop is not there
* in then returns 0
*/
function countNodesinLoop( list) {
var slow_p = list, fast_p = list;
while (slow_p != null && fast_p != null && fast_p.next != null) {
slow_p = slow_p.next;
fast_p = fast_p.next.next;
/*
* If slow_p and fast_p meet at some point then there is a loop
*/
if (slow_p == fast_p)
return countNodes(slow_p);
}
/* Return 0 to indicate that there is no loop */
return 0;
}
function newNode(key) {
temp = new Node(key);
return temp;
}
/* Driver program to test above function */
head = newNode(1);
head.next = newNode(2);
head.next.next = newNode(3);
head.next.next.next = newNode(4);
head.next.next.next.next = newNode(5);
/* Create a loop for testing */
head.next.next.next.next.next = head.next;
document.write(countNodesinLoop(head));
// This code contributed by gauravrajput1
</script>
Publicación traducida automáticamente
Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA