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Check if two Linked Lists are permutations of each other
  • Last Updated : 15 Dec, 2020

Given two singly Linked list of integer data. The task is to write a program that efficiently checks if two linked lists are permutations of each other.

Examples:  

Input: 1 -> 2 -> 3 -> 4 -> 5
        2 -> 1 -> 3 -> 5 -> 4
Output: Yes

Input: 10 -> 20 -> 30 -> 40
        20 -> 50 -> 60 -> 70
Output: No

Approach: Do the following for both linked lists:  

  1. Take a temporary node pointing to the head of the linked list.
  2. Start traversing through the linked list, and keep sum and multiplications of data of nodes.

Note : After having sum and multiplication of both linked list, check if sum and multiplication of both linked lists are equal. If they are equal, it means linked lists are permutations of each other, else not.

Below is the implementation of the above approach:  



C++




// C++ program to check if linked lists
// are permutations of each other
#include <bits/stdc++.h>
 
using namespace std;
 
// A linked list node
struct Node {
    int data;
    struct Node* next;
};
 
/*Function to check if two linked lists
* are permutations of each other
* first : reference to head of first linked list
* second : reference to head of second linked list
*/
bool isPermutation(struct Node* first, struct Node* second)
{
 
    // Variables to keep track of sum and multiplication
    int sum1 = 0, sum2 = 0, mul1 = 1, mul2 = 1;
 
    struct Node* temp1 = first;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp1 != NULL) {
        sum1 += temp1->data;
        mul1 *= temp1->data;
        temp1 = temp1->next;
    }
 
    struct Node* temp2 = second;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp2 != NULL) {
        sum2 += temp2->data;
        mul2 *= temp2->data;
        temp2 = temp2->next;
    }
 
    return ((sum1 == sum2) && (mul1 == mul2));
}
 
// Function to add a node at the
// beginning of Linked 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;
}
 
// Driver program to test above function
int main()
{
    struct Node* first = NULL;
 
    /* First constructed linked list is:
    12 -> 35 -> 1 -> 10 -> 34 -> 1 */
    push(&first, 1);
    push(&first, 34);
    push(&first, 10);
    push(&first, 1);
    push(&first, 35);
    push(&first, 12);
 
    struct Node* second = NULL;
    /* Second constructed linked list is:
    35 -> 1 -> 12 -> 1 -> 10 -> 34 */
    push(&second, 35);
    push(&second, 1);
    push(&second, 12);
    push(&second, 1);
    push(&second, 10);
    push(&second, 34);
 
    if (isPermutation(first, second)) {
        cout << "Yes" << endl;
    }
    else {
        cout << "No" << endl;
    }
 
    return 0;
}

Java




// Java program to check if linked lists
// are permutations of each other
import java.util.*;
 
class GFG
{
static class Node
{
    int data;
    Node next;
};
 
/*Function to check if two linked lists
* are permutations of each other
* first : reference to head of first linked list
* second : reference to head of second linked list
*/
static boolean isPermutation(Node first,
                             Node second)
{
 
    // Variables to keep track of
    // sum and multiplication
    int sum1 = 0, sum2 = 0,
        mul1 = 1, mul2 = 1;
 
    Node temp1 = first;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp1 != null)
    {
        sum1 += temp1.data;
        mul1 *= temp1.data;
        temp1 = temp1.next;
    }
 
    Node temp2 = second;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp2 != null)
    {
        sum2 += temp2.data;
        mul2 *= temp2.data;
        temp2 = temp2.next;
    }
 
    return ((sum1 == sum2) &&
            (mul1 == mul2));
}
 
// Function to add a node at the
// beginning of Linked List
static Node 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;
    return head_ref;
}
 
// Driver Code
public static void main(String[] args)
{
    Node first = null;
 
    /* First constructed linked list is:
    12 . 35 . 1 . 10 . 34 . 1 */
    first = push(first, 1);
    first = push(first, 34);
    first = push(first, 10);
    first = push(first, 1);
    first = push(first, 35);
    first = push(first, 12);
 
    Node second = null;
     
    /* Second constructed linked list is:
    35 . 1 . 12 . 1 . 10 . 34 */
    second = push(second, 35);
    second = push(second, 1);
    second = push(second, 12);
    second = push(second, 1);
    second = push(second, 10);
    second = push(second, 34);
 
    if (isPermutation(first, second))
    {
        System.out.print("Yes");
    }
    else
    {
        System.out.print("No");
    }
}
}
 
// This code is contributed by 29AjayKumar

Python3




# Python3 program to check if linked lists
# are permutations of each other
class Node:
     
    def __init__(self):
         
        self.data = 0
        self.next = None
 
# Function to check if two linked lists
# are permutations of each other
# first : reference to head of first linked list
# second : reference to head of second linked list
def isPermutation(first, second):
     
    # Variables to keep track of
    # sum and multiplication
    sum1 = 0
    sum2 = 0
    mul1 = 1
    mul2 = 1
  
    temp1 = first
  
    # Traversing through linked list
    # and calculating sum and multiply
    while (temp1 != None):
        sum1 += temp1.data
        mul1 *= temp1.data
        temp1 = temp1.next
 
    temp2 = second
     
    # Traversing through linked list
    # and calculating sum and multiply
    while (temp2 != None):
        sum2 += temp2.data
        mul2 *= temp2.data
        temp2 = temp2.next
     
    return ((sum1 == sum2) and (mul1 == mul2))
 
# Function to add a node at the
# beginning of Linked List
def push(head_ref, new_data):
     
    # Allocate node
    new_node = 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
    return head_ref
 
# Driver Code
if __name__=='__main__':
     
    first = None
  
    # First constructed linked list is:
    # 12 . 35 . 1 . 10 . 34 . 1
    first = push(first, 1)
    first = push(first, 34)
    first = push(first, 10)
    first = push(first, 1)
    first = push(first, 35)
    first = push(first, 12)
  
    second = None
      
    # Second constructed linked list is:
    # 35 . 1 . 12 . 1 . 10 . 34
    second = push(second, 35)
    second = push(second, 1)
    second = push(second, 12)
    second = push(second, 1)
    second = push(second, 10)
    second = push(second, 34)
  
    if (isPermutation(first, second)):
        print("Yes")
    else:
        print("No")
     
# This code is contributed by pratham76

C#




// C# program to check if linked lists
// are permutations of each other
using System;
 
class GFG
{
public class Node
{
    public int data;
    public Node next;
};
 
/*Function to check if two linked lists
* are permutations of each other
* first : reference to head of first linked list
* second : reference to head of second linked list
*/
static bool isPermutation(Node first,
                          Node second)
{
 
    // Variables to keep track of
    // sum and multiplication
    int sum1 = 0, sum2 = 0,
        mul1 = 1, mul2 = 1;
 
    Node temp1 = first;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp1 != null)
    {
        sum1 += temp1.data;
        mul1 *= temp1.data;
        temp1 = temp1.next;
    }
 
    Node temp2 = second;
 
    // Traversing through linked list
    // and calculating sum and multiply
    while (temp2 != null)
    {
        sum2 += temp2.data;
        mul2 *= temp2.data;
        temp2 = temp2.next;
    }
 
    return ((sum1 == sum2) &&
            (mul1 == mul2));
}
 
// Function to add a node at the
// beginning of Linked List
static Node 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;
    return head_ref;
}
 
// Driver Code
public static void Main(String[] args)
{
    Node first = null;
 
    /* First constructed linked list is:
    12 . 35 . 1 . 10 . 34 . 1 */
    first = push(first, 1);
    first = push(first, 34);
    first = push(first, 10);
    first = push(first, 1);
    first = push(first, 35);
    first = push(first, 12);
 
    Node second = null;
     
    /* Second constructed linked list is:
    35 . 1 . 12 . 1 . 10 . 34 */
    second = push(second, 35);
    second = push(second, 1);
    second = push(second, 12);
    second = push(second, 1);
    second = push(second, 10);
    second = push(second, 34);
 
    if (isPermutation(first, second))
    {
        Console.Write("Yes");
    }
    else
    {
        Console.Write("No");
    }
}
}
 
// This code is contributed by PrinciRaj1992
Output: 
Yes

 

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