Reverse Doubly Linked List

Medium Doubly Linked List: Utility

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Problem Statement

Write a C program to reverse a doubly linked list by swapping the next and prev pointers of every node, then print the reversed list.

Input Format

First line contains n. Second line contains n elements.

Output Format

Print the reversed doubly linked list separated by spaces.

Constraints

1 <= n <= 100

Sample Input

5
1 2 3 4 5

Sample Output

5 4 3 2 1

Explanation

Iterate through the list and swap the `next` and `prev` pointers for each node, updating the head and tail references accordingly.

Starter Code

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

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

int main() {
    int n;
    if (scanf("%d", &n) == 1) {
        struct Node *head = NULL, *tail = NULL;
        for (int i = 0; i < n; i++) {
            int val;
            scanf("%d", &val);
            struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));
            newNode->data = val;
            newNode->next = NULL;
            newNode->prev = tail;
            if (head == NULL) {
                head = newNode;
                tail = newNode;
            } else {
                tail->next = newNode;
                tail = newNode;
            }
        }
        // Write your code here to reverse doubly linked list
    }
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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