Find a triplet from three linked lists with a sum equal to a given number in C++

In this tutorial, we are going to write a program that finds the triplet in the linked list whose sum is equal to the given number.

Let's see the steps to solve the problem.

• Create a struct node for the linked list.

• Create the linked list with dummy data.

• Write three inner loops for three elements which iterate until the end of the linked list.

  • Add the three elements.

  • Compare the sum with the given number.

  • If both are equal, then print the elements and break the loops.

Example

Let's see the code.

#include <bits/stdc++.h>
using namespace std;
class Node {
   public:
   int data;
   Node* next;
};
void insertNewNode(Node** head_ref, int new_data) {
   Node* new_node = new Node();
   new_node->data = new_data;
   new_node->next = (*head_ref);
   *head_ref = new_node;
}
void findTriplet(Node *head_one, Node *head_two, Node *head_three, int givenNumber) {
   bool is_triplet_found = false;
   Node *a = head_one;
   while (a != NULL) {
      Node *b = head_two;
      while (b != NULL) {
         Node *c = head_three;
         while (c != NULL) {
            int sum = a->data + b->data + c->data;
            if (sum == givenNumber) {
               cout << a->data << " " << b->data << " " << c->data << endl;
               is_triplet_found = true;
               break;
            }
            c = c->next;
         }
         if (is_triplet_found) {
            break;
         }
         b = b->next;
      }
      if (is_triplet_found) {
         break;
      }
      a = a->next;
   }
   if (!is_triplet_found) {
      cout << "No triplet found" << endl;
   }
}
int main() {
   Node* head_one = NULL;
   Node* head_two = NULL;
   Node* head_three = NULL;
   insertNewNode (&head_one, 4);
   insertNewNode (&head_one, 3);
   insertNewNode (&head_one, 2);
   insertNewNode (&head_one, 1);
   insertNewNode (&head_two, 4);
   insertNewNode (&head_two, 3);
   insertNewNode (&head_two, 2);
   insertNewNode (&head_two, 1);
   insertNewNode (&head_three, 1);
   insertNewNode (&head_three, 2);
   insertNewNode (&head_three, 3);
   insertNewNode (&head_three, 4);
   findTriplet(head_one, head_two, head_three, 9);
   findTriplet(head_one, head_two, head_three, 100);
   return 0;
}

Output

If you run the above code, then you will get the following result.

1 4 4
No triplet found

Conclusion

If you have any queries in the tutorial, mention them in the comment section.