DSA P2 3

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

typedef struct node
{
    int val;
    struct node* prev;
    struct node* next;
} Node;

Node* genNode(int val, Node* prev, Node* next)
{
    Node* node = (Node*)malloc(sizeof(Node));

    node->val = val;
    node->prev = prev;
    node->next = next;

    return node;
}

void printList(Node* head, Node* tail)
{
    Node* cur = head;
    printf("normal:\n");
    while (cur != NULL)
    {
        printf("%d ", cur->val);
        cur = cur->next;
    }
    printf("\nreverse:\n");
    cur = tail;
    while (cur != NULL)
    {
        printf("%d ", cur->val);
        cur = cur->prev;
    }
    printf("\n");
}

int main()
{
    int numNodes;
    scanf("%d", &numNodes);

    Node* head = genNode(0, NULL, NULL);
    Node* cur = head;

    for (int i = 0; i < numNodes; i++)
    {
        int value;
        scanf("%d", &value);

        cur->val = value;
        cur->next = genNode(0, NULL, NULL);
        cur->next->prev = cur;
        cur = cur->next;
    }

    Node* tail = cur->prev;
    tail->next = NULL;

    printList(head, tail);



    int k;
    scanf("%d", &k);
    Node* newHead = tail;
    Node* prevNode = tail;

    for (int i = 0; i < k; i++)
    {
        cur = prevNode;
        prevNode = cur->prev;
        cur->prev = cur->next;

        cur->next = prevNode;
    }

    if (prevNode != NULL)
        prevNode->next = NULL;
    if (k != numNodes)
    {
        tail = prevNode;
        cur->next = head;
        head->prev = cur;
    }
    else
    {
        tail = cur;
    }
    head = newHead;

    printList(head, tail);




    return 0;
}