Dada una lista enlazada y dos claves en ella, intercambie Nodes por dos claves dadas. Los Nodes deben intercambiarse cambiando los enlaces. El intercambio de datos de Nodes puede ser costoso en muchas situaciones cuando los datos contienen muchos campos. Se puede suponer que todas las claves de la lista enlazada son distintas.
Ejemplos:
C++
/* This program swaps the nodes of linked list rather
than swapping the field from the nodes.*/
#include <bits/stdc++.h>
using namespace std;
/* A linked list node */
class Node {
public:
int data;
Node* next;
};
/* Function to swap nodes x and y in linked list by
changing links */
void swapNodes(Node** head_ref, int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
// Search for x (keep track of prevX and CurrX
Node *prevX = NULL, *currX = *head_ref;
while (currX && currX->data != x) {
prevX = currX;
currX = currX->next;
}
// Search for y (keep track of prevY and CurrY
Node *prevY = NULL, *currY = *head_ref;
while (currY && currY->data != y) {
prevY = currY;
currY = currY->next;
}
// If either x or y is not present, nothing to do
if (currX == NULL || currY == NULL)
return;
// If x is not head of linked list
if (prevX != NULL)
prevX->next = currY;
else // Else make y as new head
*head_ref = currY;
// If y is not head of linked list
if (prevY != NULL)
prevY->next = currX;
else // Else make x as new head
*head_ref = currX;
// Swap next pointers
Node* temp = currY->next;
currY->next = currX->next;
currX->next = temp;
}
/* Function to add a node at the beginning of List */
void push(Node** head_ref, int new_data)
{
/* allocate node */
Node* new_node = new Node();
/* put in the data */
new_node->data = new_data;
/* link the old list off the new node */
new_node->next = (*head_ref);
/* move the head to point to the new node */
(*head_ref) = new_node;
}
/* Function to print nodes in a given linked list */
void printList(Node* node)
{
while (node != NULL) {
cout << node->data << " ";
node = node->next;
}
}
/* Driver program to test above function */
int main()
{
Node* start = NULL;
/* The constructed linked list is:
1->2->3->4->5->6->7 */
push(&start, 7);
push(&start, 6);
push(&start, 5);
push(&start, 4);
push(&start, 3);
push(&start, 2);
push(&start, 1);
cout << "Linked list before calling swapNodes() ";
printList(start);
swapNodes(&start, 4, 3);
cout << "\nLinked list after calling swapNodes() ";
printList(start);
return 0;
}
// This is code is contributed by rathbhupendra
C
/* This program swaps the nodes of linked list rather
than swapping the field from the nodes.*/
#include <stdio.h>
#include <stdlib.h>
/* A linked list node */
struct Node {
int data;
struct Node* next;
};
/* Function to swap nodes x and y in linked list by
changing links */
void swapNodes(struct Node** head_ref, int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
// Search for x (keep track of prevX and CurrX
struct Node *prevX = NULL, *currX = *head_ref;
while (currX && currX->data != x) {
prevX = currX;
currX = currX->next;
}
// Search for y (keep track of prevY and CurrY
struct Node *prevY = NULL, *currY = *head_ref;
while (currY && currY->data != y) {
prevY = currY;
currY = currY->next;
}
// If either x or y is not present, nothing to do
if (currX == NULL || currY == NULL)
return;
// If x is not head of linked list
if (prevX != NULL)
prevX->next = currY;
else // Else make y as new head
*head_ref = currY;
// If y is not head of linked list
if (prevY != NULL)
prevY->next = currX;
else // Else make x as new head
*head_ref = currX;
// Swap next pointers
struct Node* temp = currY->next;
currY->next = currX->next;
currX->next = temp;
}
/* Function to add a node at the beginning of List */
void push(struct Node** head_ref, int new_data)
{
/* allocate node */
struct Node* new_node
= (struct Node*)malloc(sizeof(struct Node));
/* put in the data */
new_node->data = new_data;
/* link the old list off the new node */
new_node->next = (*head_ref);
/* move the head to point to the new node */
(*head_ref) = new_node;
}
/* Function to print nodes in a given linked list */
void printList(struct Node* node)
{
while (node != NULL) {
printf("%d ", node->data);
node = node->next;
}
}
/* Driver program to test above function */
int main()
{
struct Node* start = NULL;
/* The constructed linked list is:
1->2->3->4->5->6->7 */
push(&start, 7);
push(&start, 6);
push(&start, 5);
push(&start, 4);
push(&start, 3);
push(&start, 2);
push(&start, 1);
printf("\n Linked list before calling swapNodes() ");
printList(start);
swapNodes(&start, 4, 3);
printf("\n Linked list after calling swapNodes() ");
printList(start);
return 0;
}
Java
// Java program to swap two given nodes of a linked list
class Node {
int data;
Node next;
Node(int d)
{
data = d;
next = null;
}
}
class LinkedList {
Node head; // head of list
/* Function to swap Nodes x and y in linked list by
changing links */
public void swapNodes(int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
// Search for x (keep track of prevX and CurrX)
Node prevX = null, currX = head;
while (currX != null && currX.data != x) {
prevX = currX;
currX = currX.next;
}
// Search for y (keep track of prevY and currY)
Node prevY = null, currY = head;
while (currY != null && currY.data != y) {
prevY = currY;
currY = currY.next;
}
// If either x or y is not present, nothing to do
if (currX == null || currY == null)
return;
// If x is not head of linked list
if (prevX != null)
prevX.next = currY;
else // make y the new head
head = currY;
// If y is not head of linked list
if (prevY != null)
prevY.next = currX;
else // make x the new head
head = currX;
// Swap next pointers
Node temp = currX.next;
currX.next = currY.next;
currY.next = temp;
}
/* Function to add Node at beginning of list. */
public void push(int new_data)
{
/* 1. alloc the Node and put the data */
Node new_Node = new Node(new_data);
/* 2. Make next of new Node as head */
new_Node.next = head;
/* 3. Move the head to point to new Node */
head = new_Node;
}
/* This function prints contents of linked list starting
from the given Node */
public void printList()
{
Node tNode = head;
while (tNode != null) {
System.out.print(tNode.data + " ");
tNode = tNode.next;
}
}
/* Driver program to test above function */
public static void main(String[] args)
{
LinkedList llist = new LinkedList();
/* The constructed linked list is:
1->2->3->4->5->6->7 */
llist.push(7);
llist.push(6);
llist.push(5);
llist.push(4);
llist.push(3);
llist.push(2);
llist.push(1);
System.out.print(
"\n Linked list before calling swapNodes() ");
llist.printList();
llist.swapNodes(4, 3);
System.out.print(
"\n Linked list after calling swapNodes() ");
llist.printList();
}
}
// This code is contributed by Rajat Mishra
Python
# Python program to swap two given nodes of a linked list class LinkedList(object): def __init__(self): self.head = None # head of list class Node(object): def __init__(self, d): self.data = d self.next = None # Function to swap Nodes x and y in linked list by # changing links def swapNodes(self, x, y): # Nothing to do if x and y are same if x == y: return # Search for x (keep track of prevX and CurrX) prevX = None currX = self.head while currX != None and currX.data != x: prevX = currX currX = currX.next # Search for y (keep track of prevY and currY) prevY = None currY = self.head while currY != None and currY.data != y: prevY = currY currY = currY.next # If either x or y is not present, nothing to do if currX == None or currY == None: return # If x is not head of linked list if prevX != None: prevX.next = currY else: # make y the new head self.head = currY # If y is not head of linked list if prevY != None: prevY.next = currX else: # make x the new head self.head = currX # Swap next pointers temp = currX.next currX.next = currY.next currY.next = temp # Function to add Node at beginning of list. def push(self, new_data): # 1. alloc the Node and put the data new_Node = self.Node(new_data) # 2. Make next of new Node as head new_Node.next = self.head # 3. Move the head to point to new Node self.head = new_Node # This function prints contents of linked list starting # from the given Node def printList(self): tNode = self.head while tNode != None: print tNode.data, tNode = tNode.next # Driver program to test above function llist = LinkedList() # The constructed linked list is: # 1->2->3->4->5->6->7 llist.push(7) llist.push(6) llist.push(5) llist.push(4) llist.push(3) llist.push(2) llist.push(1) print "Linked list before calling swapNodes() " llist.printList() llist.swapNodes(4, 3) print "\nLinked list after calling swapNodes() " llist.printList() # This code is contributed by BHAVYA JAIN
C#
// C# program to swap two given
// nodes of a linked list
using System;
class Node {
public int data;
public Node next;
public Node(int d)
{
data = d;
next = null;
}
}
public class LinkedList {
Node head; // head of list
/* Function to swap Nodes x and y in
linked list by changing links */
public void swapNodes(int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
// Search for x (keep track of prevX and CurrX)
Node prevX = null, currX = head;
while (currX != null && currX.data != x) {
prevX = currX;
currX = currX.next;
}
// Search for y (keep track of prevY and currY)
Node prevY = null, currY = head;
while (currY != null && currY.data != y) {
prevY = currY;
currY = currY.next;
}
// If either x or y is not present, nothing to do
if (currX == null || currY == null)
return;
// If x is not head of linked list
if (prevX != null)
prevX.next = currY;
else // make y the new head
head = currY;
// If y is not head of linked list
if (prevY != null)
prevY.next = currX;
else // make x the new head
head = currX;
// Swap next pointers
Node temp = currX.next;
currX.next = currY.next;
currY.next = temp;
}
/* Function to add Node at beginning of list. */
public void push(int new_data)
{
/* 1. alloc the Node and put the data */
Node new_Node = new Node(new_data);
/* 2. Make next of new Node as head */
new_Node.next = head;
/* 3. Move the head to point to new Node */
head = new_Node;
}
/* This function prints contents of linked list
starting from the given Node */
public void printList()
{
Node tNode = head;
while (tNode != null) {
Console.Write(tNode.data + " ");
tNode = tNode.next;
}
}
/* Driver code */
public static void Main(String[] args)
{
LinkedList llist = new LinkedList();
/* The constructed linked list is:
1->2->3->4->5->6->7 */
llist.push(7);
llist.push(6);
llist.push(5);
llist.push(4);
llist.push(3);
llist.push(2);
llist.push(1);
Console.Write(
"\n Linked list before calling swapNodes() ");
llist.printList();
llist.swapNodes(4, 3);
Console.Write(
"\n Linked list after calling swapNodes() ");
llist.printList();
}
}
// This code is contributed by 29AjayKumar
Javascript
<script>
// JavaScript program to swap two
// given nodes of a linked list
class Node {
constructor(val) {
this.data = val;
this.next = null;
}
}
var head; // head of list
/*
Function to swap Nodes x and y in
linked list by changing links
*/
function swapNodes(x , y) {
// Nothing to do if x and y are same
if (x == y)
return;
// Search for x (keep track of prevX and CurrX)
var prevX = null, currX = head;
while (currX != null && currX.data != x) {
prevX = currX;
currX = currX.next;
}
// Search for y (keep track of prevY and currY)
var prevY = null, currY = head;
while (currY != null && currY.data != y) {
prevY = currY;
currY = currY.next;
}
// If either x or y is not present, nothing to do
if (currX == null || currY == null)
return;
// If x is not head of linked list
if (prevX != null)
prevX.next = currY;
else // make y the new head
head = currY;
// If y is not head of linked list
if (prevY != null)
prevY.next = currX;
else // make x the new head
head = currX;
// Swap next pointers
var temp = currX.next;
currX.next = currY.next;
currY.next = temp;
}
/* Function to add Node at beginning of list. */
function push(new_data) {
/* 1. alloc the Node and put the data */
var new_Node = new Node(new_data);
/* 2. Make next of new Node as head */
new_Node.next = head;
/* 3. Move the head to point to new Node */
head = new_Node;
}
/*
This function prints contents of
linked list starting from the given Node
*/
function printList() {
var tNode = head;
while (tNode != null) {
document.write(tNode.data + " ");
tNode = tNode.next;
}
}
/* Driver program to test above function */
/*
The constructed linked list is:
1->2->3->4->5->6->7
*/
push(7);
push(6);
push(5);
push(4);
push(3);
push(2);
push(1);
document.write(
" Linked list before calling swapNodes()<br/> ")
;
printList();
swapNodes(4, 3);
document.write(
"<br/> Linked list after calling swapNodes() <br/>"
);
printList();
// This code is contributed by todaysgaurav
</script>
C++
// C++ program to swap two given nodes of a linked list
#include <iostream>
using namespace std;
// A linked list node class
class Node {
public:
int data;
class Node* next;
// constructor
Node(int val, Node* next)
: data(val)
, next(next)
{
}
// print list from this to last till null
void printList()
{
Node* node = this;
while (node != NULL) {
cout << node->data << " ";
node = node->next;
}
cout << endl;
}
};
// Function to add a node at the beginning of List
void push(Node** head_ref, int new_data)
{
// allocate node
(*head_ref) = new Node(new_data, *head_ref);
}
void swap(Node*& a, Node*& b)
{
Node* temp = a;
a = b;
b = temp;
}
void swapNodes(Node** head_ref, int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
Node **a = NULL, **b = NULL;
// search for x and y in the linked list
// and store their pointer in a and b
while (*head_ref) {
if ((*head_ref)->data == x)
a = head_ref;
else if ((*head_ref)->data == y)
b = head_ref;
head_ref = &((*head_ref)->next);
}
// if we have found both a and b
// in the linked list swap current
// pointer and next pointer of these
if (a && b) {
swap(*a, *b);
swap(((*a)->next), ((*b)->next));
}
}
// Driver code
int main()
{
Node* start = NULL;
// The constructed linked list is:
// 1->2->3->4->5->6->7
push(&start, 7);
push(&start, 6);
push(&start, 5);
push(&start, 4);
push(&start, 3);
push(&start, 2);
push(&start, 1);
cout << "Linked list before calling swapNodes() ";
start->printList();
swapNodes(&start, 6, 1);
cout << "Linked list after calling swapNodes() ";
start->printList();
}
// This code is contributed by Sania Kumari Gupta
// (kriSania804)
C
// C program to swap two given nodes of a linked list
#include <stdio.h>
#include <stdlib.h>
/* A linked list node */
typedef struct Node {
int data;
struct Node* next;
} Node;
/* Function to add a node at the beginning of List */
void push(struct Node** head_ref, int new_data)
{
/* allocate node */
Node* new_node = (Node*)malloc(sizeof
/* put in the data */
new_node->data
/* link the old list off the new node */
new_node->next =
/* move the head to point to the new node */
(*head_ref) = new_node;
}
/* Function to print nodes in a given linked list */
void printList(Node* node)
{
while (node != NULL) {
printf("%d ", node->data);
node = node->next;
}
}
void swap(Node* a, Node* b)
{
Node temp = *a;
*a = *b;
*b = temp;
}
void swapNodes(Node** head_ref, int x, int y)
{
// Nothing to do if x and y are same
if (x == y)
return;
Node **a = NULL, **b = NULL;
// search for x and y in the linked list
// and store their pointer in a and b
while (*head_ref) {
if ((*head_ref)->data == x)
a = head_ref;
else if ((*head_ref)->data == y)
b = head_ref;
head_ref = &((*head_ref)->next);
}
// if we have found both a and b in the linked list swap
// current pointer and next pointer of these
if (a && b) {
swap(*a, *b);
swap(((*a)->next), ((*b)->next));
}
}
// Driver code
int main()
{
struct Node* start = NULL;
/* The constructed linked list is:
1->2->3->4->5->6->7 */
push(&start, 7);
push(&start, 6);
push(&start, 5);
push(&start, 4);
push(&start, 3);
push(&start, 2);
push(&start, 1);
printf("Linked list before calling swapNodes() ");
printList(start);
printf("\n");
swapNodes(&start, 6, 1);
printf("Linked list after calling swapNodes() ");
printList(start);
}
// This code is contributed by Sania Kumari Gupta
// (kriSania804)
Java
// Java program to swap two given nodes of a linked list
public class Solution {
// Represent a node of the singly linked list
class Node {
int data;
Node next;
public Node(int data)
{
this.data = data;
this.next = null;
}
}
// Represent the head and tail of the singly linked list
public Node head = null;
public Node tail = null;
// addNode() will add a new node to the list
public void addNode(int data)
{
// Create a new node
Node newNode = new Node(data);
// Checks if the list is empty
if (head == null) {
// If list is empty, both head and
// tail will point to new node
head = newNode;
tail = newNode;
}
else {
// newNode will be added after tail such that
// tail's next will point to newNode
tail.next = newNode;
// newNode will become new tail of the list
tail = newNode;
}
}
// swap() will swap the given two nodes
public void swap(int n1, int n2)
{
Node prevNode1 = null, prevNode2 = null,
node1 = head, node2 = head;
// Checks if list is empty
if (head == null) {
return;
}
// If n1 and n2 are equal, then
// list will remain the same
if (n1 == n2)
return;
// Search for node1
while (node1 != null && node1.data != n1) {
prevNode1 = node1;
node1 = node1.next;
}
// Search for node2
while (node2 != null && node2.data != n2) {
prevNode2 = node2;
node2 = node2.next;
}
if (node1 != null && node2 != null) {
// If previous node to node1 is not null then,
// it will point to node2
if (prevNode1 != null)
prevNode1.next = node2;
else
head = node2;
// If previous node to node2 is not null then,
// it will point to node1
if (prevNode2 != null)
prevNode2.next = node1;
else
head = node1;
// Swaps the next nodes of node1 and node2
Node temp = node1.next;
node1.next = node2.next;
node2.next = temp;
}
else {
System.out.println("Swapping is not possible");
}
}
// display() will display all the
// nodes present in the list
public void display()
{
// Node current will point to head
Node current = head;
if (head == null) {
System.out.println("List is empty");
return;
}
while (current != null) {
// Prints each node by incrementing pointer
System.out.print(current.data + " ");
current = current.next;
}
System.out.println();
}
public static void main(String[] args)
{
Solution sList = new Solution();
// Add nodes to the list
sList.addNode(1);
sList.addNode(2);
sList.addNode(3);
sList.addNode(4);
sList.addNode(5);
sList.addNode(6);
sList.addNode(7);
System.out.println("Original list: ");
sList.display();
// Swaps the node 2 with node 5
sList.swap(6, 1);
System.out.println("List after swapping nodes: ");
sList.display();
}
}
Python3
# Python3 program to swap two given
# nodes of a linked list
# A linked list node class
class Node:
# constructor
def __init__(self, val=None, next1=None):
self.data = val
self.next = next1
# print list from this
# to last till None
def printList(self):
node = self
while (node != None):
print(node.data, end=" ")
node = node.next
print(" ")
# Function to add a node
# at the beginning of List
def push(head_ref, new_data):
# allocate node
(head_ref) = Node(new_data, head_ref)
return head_ref
def swapNodes(head_ref, x, y):
head = head_ref
# Nothing to do if x and y are same
if (x == y):
return None
a = None
b = None
# search for x and y in the linked list
# and store their pointer in a and b
while (head_ref.next != None):
if ((head_ref.next).data == x):
a = head_ref
elif ((head_ref.next).data == y):
b = head_ref
head_ref = ((head_ref).next)
# if we have found both a and b
# in the linked list swap current
# pointer and next pointer of these
if (a != None and b != None):
temp = a.next
a.next = b.next
b.next = temp
temp = a.next.next
a.next.next = b.next.next
b.next.next = temp
return head
# Driver code
start = None
# The constructed linked list is:
# 1.2.3.4.5.6.7
start = push(start, 7)
start = push(start, 6)
start = push(start, 5)
start = push(start, 4)
start = push(start, 3)
start = push(start, 2)
start = push(start, 1)
print("Linked list before calling swapNodes() ")
start.printList()
start = swapNodes(start, 6, 1)
print("Linked list after calling swapNodes() ")
start.printList()
# This code is contributed by Arnab Kundu
C#
// C# program to swap two
// given nodes of a linked list
using System;
class GFG {
// A linked list node class
public class Node {
public int data;
public Node next;
// constructor
public Node(int val, Node next1)
{
data = val;
next = next1;
}
// print list from this
// to last till null
public void printList()
{
Node node = this;
while (node != null) {
Console.Write(node.data + " ");
node = node.next;
}
Console.WriteLine();
}
}
// Function to add a node
// at the beginning of List
static Node push(Node head_ref, int new_data)
{
// allocate node
(head_ref) = new Node(new_data, head_ref);
return head_ref;
}
static Node swapNodes(Node head_ref, int x, int y)
{
Node head = head_ref;
// Nothing to do if x and y are same
if (x == y)
return null;
Node a = null, b = null;
// search for x and y in the linked list
// and store their pointer in a and b
while (head_ref.next != null) {
if ((head_ref.next).data == x) {
a = head_ref;
}
else if ((head_ref.next).data == y) {
b = head_ref;
}
head_ref = ((head_ref).next);
}
// if we have found both a and b
// in the linked list swap current
// pointer and next pointer of these
if (a != null && b != null) {
Node temp = a.next;
a.next = b.next;
b.next = temp;
temp = a.next.next;
a.next.next = b.next.next;
b.next.next = temp;
}
return head;
}
// Driver code
public static void Main()
{
Node start = null;
// The constructed linked list is:
// 1.2.3.4.5.6.7
start = push(start, 7);
start = push(start, 6);
start = push(start, 5);
start = push(start, 4);
start = push(start, 3);
start = push(start, 2);
start = push(start, 1);
Console.Write(
"Linked list before calling swapNodes() ");
start.printList();
start = swapNodes(start, 6, 1);
Console.Write(
"Linked list after calling swapNodes() ");
start.printList();
}
}
/* This code contributed by PrinciRaj1992 */
Javascript
<script>
// javascript program to swap two given nodes of a linked list
// Represent a node of the singly linked list
class Node {
constructor(val) {
this.data = val;
this.next = null;
}
}
// Represent the head and tail of the singly linked list
var head = null;
var tail = null;
// addNode() will add a new node to the list
function addNode(data) {
// Create a new node
var newNode = new Node(data);
// Checks if the list is empty
if (head == null) {
// If list is empty, both head and
// tail will point to new node
head = newNode;
tail = newNode;
} else {
// newNode will be added after tail such that
// tail's next will point to newNode
tail.next = newNode;
// newNode will become new tail of the list
tail = newNode;
}
}
// swap() will swap the given two nodes
function swap(n1 , n2) {
var prevNode1 = null, prevNode2 = null, node1 = head, node2 = head;
// Checks if list is empty
if (head == null) {
return;
}
// If n1 and n2 are equal, then
// list will remain the same
if (n1 == n2)
return;
// Search for node1
while (node1 != null && node1.data != n1) {
prevNode1 = node1;
node1 = node1.next;
}
// Search for node2
while (node2 != null && node2.data != n2) {
prevNode2 = node2;
node2 = node2.next;
}
if (node1 != null && node2 != null) {
// If previous node to node1 is not null then,
// it will point to node2
if (prevNode1 != null)
prevNode1.next = node2;
else
head = node2;
// If previous node to node2 is not null then,
// it will point to node1
if (prevNode2 != null)
prevNode2.next = node1;
else
head = node1;
// Swaps the next nodes of node1 and node2
var temp = node1.next;
node1.next = node2.next;
node2.next = temp;
} else {
document.write("Swapping is not possible");
}
}
// display() will display all the
// nodes present in the list
function display() {
// Node current will point to head
var current = head;
if (head == null) {
document.write("List is empty");
return;
}
while (current != null) {
// Prints each node by incrementing pointer
document.write(current.data + " ");
current = current.next;
}
document.write();
}
// Add nodes to the list
addNode(1);
addNode(2);
addNode(3);
addNode(4);
addNode(5);
addNode(6);
addNode(7);
document.write("Original list:<br/> ");
display();
// Swaps the node 2 with node 5
swap(6, 1);
document.write("<br/>List after swapping nodes: <br/>");
display();
// This code contributed by aashish1995
</script>
Publicación traducida automáticamente
Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA