N D04 - Harry Potter and the Prisoner of Azkaban.c

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>
typedef struct LinkedListNode LinkedListNode;

struct LinkedListNode {
    int val;
    LinkedListNode *next;
};

LinkedListNode* _insert_node_into_singlylinkedlist(LinkedListNode *head, LinkedListNode *tail, int val) {
    if (head == NULL) {
        head = (LinkedListNode *) (malloc(sizeof(LinkedListNode)));
        head->val = val;
        head->next = NULL;
        tail = head;
    }
    else {
        LinkedListNode *node = (LinkedListNode *) (malloc(sizeof(LinkedListNode)));
        node->val = val;
        node->next = NULL;
        tail->next = node;
        tail = tail->next;
    }
    return tail;
}


/*
 * Complete the function below.
 */
/*
For your reference:
LinkedListNode {
    int val;
    LinkedListNode *next;
};
*/
LinkedListNode* addLists(LinkedListNode* list1, LinkedListNode* list2) {
    int a[100], b[100];
    int i = 0, j = 0;
    struct LinkedListNode *temp = (struct LinkedListNode *)malloc(sizeof(struct LinkedListNode));

    while (list1)
    {
        a[i++] = list1->val;
        list1 = list1->next;
    }
    while (list2)
    {
        b[j++] = list2->val;
        list2 = list2->next;
    }
    int sizea = i, sizeb = j;
    if (i >= j)    {
        while (i && j)
        {
            a[--i] += b[--j];
        }
        for (int x = sizea - 1; x > 0; x--)
        {
            if (a[x] >= 10)
            {
                a[x] %= 10;
                a[x - 1] += 1;
            }
        }
        //  for(int x=0;x<sizea;x++)
        //      printf("%d ",a[x]);
    }
    else
    {
        while (i && j)
        {
            b[--j] += a[--i];
        }
        for (int x = sizeb - 1; x > 0; x--)
        {
            if (b[x] >= 10)
            {
                b[x] %= 10;
                b[x - 1] += 1;
            }
        }
        // for(int x=0;x<sizeb;x++)
        //    printf("%d ",b[x]);
        for (int y = 0; y < sizeb; y++)
            a[y] = b[y];

    }
    int maxs = sizea >= sizeb ? sizea : sizeb;
    // printf("%d ",maxs);
    LinkedListNode *temp1, *temphead = NULL;
    for (int co = maxs - 1; co >= 0; co--)
    {
        /*temp->val=a[co];
        temp=temp->next;
         if(temp==NULL)
             break;*/
        temp1 = ( LinkedListNode *)malloc(sizeof( LinkedListNode));
        temp1->val = a[co];
        temp1->next = temphead;
        temphead = temp1;
        //printf("%d",a[co]);
    }
    // temp->next=NULL;
    return temphead;
}

int main()
{
    FILE *f = stdout;
    char *output_path = getenv("OUTPUT_PATH");
    if (output_path) {
        f = fopen(output_path, "w");
    }

    LinkedListNode* res;
    int list1_size = 0;

    LinkedListNode* list1 = NULL;
    LinkedListNode* list1_tail = NULL;

    scanf("%d\n", &list1_size);
    for (int i = 0; i < list1_size; i++) {
        int list1_item;
        scanf("%d", &list1_item);
        list1_tail = _insert_node_into_singlylinkedlist(list1, list1_tail, list1_item);

        if (i == 0) {
            list1 = list1_tail;
        }
    }


    int list2_size = 0;

    LinkedListNode* list2 = NULL;
    LinkedListNode* list2_tail = NULL;

    scanf("%d\n", &list2_size);
    for (int i = 0; i < list2_size; i++) {
        int list2_item;
        scanf("%d", &list2_item);
        list2_tail = _insert_node_into_singlylinkedlist(list2, list2_tail, list2_item);

        if (i == 0) {
            list2 = list2_tail;
        }
    }


    res = addLists(list1, list2);
    while (res != NULL) {
        fprintf(f, "%d", res->val);
        res = res->next;
    }

    fclose(f);
    return 0;
}