How do I merge two sorted linked lists in C++?

How do I merge two sorted linked lists in C++?

You can merge two sorted linked lists by iterating through both lists and comparing their nodes. Would you like a code example?

Yes, please provide a code example.

Here's a simple implementation:

struct Node {
    int data;
    Node* next;
};

Node* mergeSortedLists(Node* l1, Node* l2) {
    if (!l1) return l2;
    if (!l2) return l1;

    Node* head = nullptr;
    if (l1->data < l2->data) {
        head = l1;
        l1 = l1->next;
    } else {
        head = l2;
        l2 = l2->next;
    }

    Node* current = head;
    while (l1 && l2) {
        if (l1->data < l2->data) {
            current->next = l1;
            l1 = l1->next;
        } else {
            current->next = l2;
            l2 = l2->next;
        }
        current = current->next;
    }
    current->next = (l1) ? l1 : l2;
    return head;
}

This function merges two sorted linked lists into one sorted list.

What is the time complexity of this algorithm?

The time complexity of this algorithm is O(n + m), where n and m are the lengths of the two linked lists. This is because we traverse each list once.