Description

Please write a program to first create a linked list. Then, based on the user's input, add the number "val" into the "place"-th position and directly print the result after addition.

請撰寫一支程式，先建立一個鏈結串列，接著根據使用者的輸入，將數字 val 新增到第 place個位置，並直接印出新增後的結果。

For example, original state: 2->3->7

例如：原始狀態：2->3->7

1. Add 5 into the 1st position, it will become: 5->2->3->7

2. 新增 5 到第 1 個位置，會變成：5->2->3->7

3. Add 9 into the 3rd position, it will become: 5->2->9->3->7

4. 新增 9 到第 3 個位置，會變成：5->2->9->3->7

Input

The first line contains multiple integers separated by spaces, terminated by -1, indicating the initial state of the linked list.

第一行輸入包含多個整數，以 -1 作為結束，代表一開始 Linked List 的狀態。

From the second line, there are multiple lines of input. Each line contains two numbers: "val" and "place" until EOF. There will be no situation where "place" is greater than the original number of nodes + 1.

第二行開始有多行輸入，每行有兩個數字：val 與 place。不會出現 place > 原節點個數+1 的情況。直到 EOF 為止。

Output

Please print the result after each addition of a number.

請印出每次新增數字後的結果。

Sample Input 1

2 3 7 -1
5 1
9 3
-17 5

Sample Output 1

5->2->3->7
5->2->9->3->7
5->2->9->3->-17->7

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

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

// Function to insert a new node at a specific position
Node* InsertAtPosition(Node* head, int val, int place) {
    Node* new_node = (Node*)malloc(sizeof(Node));
    new_node->data = val;

    // If position is 1 or list is empty, insert at the beginning
    if (place == 1 || head == NULL) {
        new_node->next = head;
        return new_node;
    }

    Node* current = head;
    int count = 1;

    // Traverse until position - 1
    while (count < place - 1 && current->next != NULL) {
        current = current->next;
        count++;
    }

    // Insert the new node
    new_node->next = current->next;
    current->next = new_node;

    return head;
}

// Function to print the linked list
void PrintList(Node* head) {
    while (head != NULL) {
        printf("%d", head->data);
        if (head->next != NULL) {
            printf("->");
        }
        head = head->next;
    }
    printf("\\n");
}

int main() {
    int num, place;
    Node* head = NULL;

    // Creating the linked list from input
    while (scanf("%d", &num) != EOF) {
        if (num == -1)
            break;
        Node* new_node = (Node*)malloc(sizeof(Node));
        new_node->data = num;
        new_node->next = NULL;
        if (head == NULL)
            head = new_node;
        else {
            Node* current = head;
            while (current->next != NULL) {
                current = current->next;
            }
            current->next = new_node;
        }
    }

    // Inputting values and positions and inserting into the list
    while (scanf("%d %d", &num, &place) != EOF) {
        head = InsertAtPosition(head, num, place);
        PrintList(head);
    }

    // Freeing allocated memory
    Node* temp;
    while (head != NULL) {
        temp = head;
        head = head->next;
        free(temp);
    }

    return 0;
}