Notes

//-------------------- head of the code ------------------------

#include <string.h>
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#define in(x) scanf(" %d", &x);
#define LinkedListNode LinkedListNode
typedef struct LinkedListNode LinkedListNode;
struct LinkedListNode {
int val;
struct LinkedListNode* next;
};


//-------------------- body of the code ------------------------

struct LinkedListNode *addToEmpty(LinkedListNode *last, int data)
{
if (last != NULL)
return last;
struct LinkedListNode *l = (struct LinkedListNode*)malloc(sizeof(struct LinkedListNode));
l -> val = data;
l -> next = l;

return l;
}

LinkedListNode* insertAtBeginning(LinkedListNode* last, int data) {
if (last == NULL)
return addToEmpty(last, data);

struct LinkedListNode *temp = (struct LinkedListNode *)malloc(sizeof(struct LinkedListNode));
temp -> val = data;
temp -> next = last -> next;
last -> next = temp;

return last;

}
LinkedListNode* insertAtEnd(LinkedListNode* last, int data) {

if (last == NULL)
return addToEmpty(last, data);
struct LinkedListNode *temp = (struct LinkedListNode *)malloc(sizeof(struct LinkedListNode));

temp -> val = data;
temp -> next = last -> next;
last -> next = temp;
last=temp;

return last;
}
LinkedListNode* deleteAtBeginning(LinkedListNode* tail) {
if(tail==NULL)
return NULL;
struct LinkedListNode *t;
if(tail==tail->next)
tail=NULL;
else
{ t=tail->next;
tail->next=tail->next->next;
free(t);}
return tail;

}
LinkedListNode* deleteAtEnd(LinkedListNode* tail) {
if(tail==NULL)
return NULL;
struct LinkedListNode *t;
if(tail==tail->next)
tail=NULL;
else
{ t=tail->next;
while(t->next!=tail)
t=t->next;
t->next=t->next->next;
free(tail);
tail=t;
}
return tail;

}


//-------------------- tail of the code ------------------------

void printForward(LinkedListNode* head) {
if (head == NULL) return;
printf("%d ", head->val);
printForward(head->next);
}
void printBackward(LinkedListNode* head) {
if (head == NULL) return;
printBackward(head->next);
printf("%d ", head->val);
}
int rng(int lim) {
if (lim == 0) return 0;
return rand()%lim;
}
int a[1005], sz = 0;
void insertt(int val, int pos) {
if (pos < 0) return;
if (pos > sz + 1) return;
sz += 1;
for (int i = sz; i > pos; i--)
a[i] = a[i - 1];
a[pos] = val;
}
void erasee(int pos) {
if (pos > sz) return;
if (pos < 1) return;
sz--;
for (int i = pos; i <= sz; i++)
a[i] = a[i + 1];
}
int check(LinkedListNode* tail) {
if (tail == NULL && sz == 0) return 1;
if (tail == NULL || sz == 0) return 0;
if (tail->val != a[sz]) return 0;
LinkedListNode* ii = tail->next;
for (int i = 1; i < sz; i++) {
if (ii == NULL) return 0;
if (a[i] != ii->val) return 0;
ii = ii->next;
}
return 1;
}
int main() {
srand(time(NULL));
int t, n; in(t); in(n);
while (t--) {
LinkedListNode* head = NULL;
sz = 0;
for (int i = 0; i < n; i++) {
int type = rng(4);
if (type == 0) {
int val = rng(1000);
head = insertAtBeginning(head, val);
insertt(val, 1);
if (!check(head)) {
printf("incorrect insertAtBeginning");
return 0;
}
}

if (type == 1) {
int val = rng(1000);
head = insertAtEnd(head, val);
insertt(val, sz + 1);
if (!check(head)) {
printf("incorrect insertAtEnd");
return 0;
}
}

if (type == 2) {
head = deleteAtBeginning(head);
erasee(1);
if (!check(head)) {
printf("incorrect deleteAtBeginning");
return 0;
}
}

if (type == 3) {
head = deleteAtEnd(head);
erasee(sz);
if (!check(head)) {
printf("incorrect deleteAtEnd");
return 0;
}
}
}
}
printf("correct");
}