Problem p02265 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

struct Node {
  int key;
  Node *next, *prev;
};

Node *nil;

Node *listSearch(int key) {
  Node *cur = nil->next;
  while (cur != nil && cur->key != key) {
    cur = cur->next;
  }
  return cur;
}

void init() {
  nil = (Node *)malloc(sizeof(Node));
  nil->next = nil;
  nil->prev = nil;
}

void printList() {
  Node *cur = nil->next;
  int isf = 0;
  while (1) {
    if (cur == nil)
      break;
    if (isf++ > 0)
      printf(" ");
    printf("%d", cur->key);
    cur = cur->next;
  }
  printf("\\n");
}

void deleteNode(Node *t) {
  if (t == nil)
    return;
  t->prev->next = t->next;
  t->next->prev = t->prev;
  free(t);
}

void deleteFirst() { deleteNode(nil->next); }

void deleteLast() { deleteNode(nil->prev); }

void deleteKey(int key) { deleteNode(listSearch(key)); }

void insert(int key) {
  Node *x = (Node *)malloc(sizeof(Node));
  x->key = key;
  x->next = nil->next;
  nil->next->prev = x;
  nil->next = x;
  x->prev = nil;
}

int main() {
  int key, n, i;
  int size = 0;
  char com[20];
  int np = 0, nd = 0;
  scanf("%d", &n);
  init();
  for (i = 0; i < n; i++) {
    scanf("%s%d", com, &key);
    if (com[0] == 'i') {
      insert(key);
      np++;
      size++;
    } else if (com[0] = 'd') {
      if (strlen(com) > 6) {
        if (com[6] == 'F')
          deleteFirst();
        else if (com[6] == 'L')
          deleteLast();
      } else {
        deleteKey(key);
        nd++;
      }
      size--;
    }
  }
  printList();

  return 0;
}

Error: TLE

Fixed submission:

#include <cstdio>
#include <cstring>
//?????¬?±??
struct Node {
  Node *next;
  Node *last;
  int number;
};

int main(void) {
  using namespace std;

  int n, num;
  char temp[20];
  Node *List, *p;

  scanf("%d", &n);

  List = NULL;
  for (int i = 0; i < n; i++) {
    scanf("%s", temp);
    if (strcmp(temp, "insert") == 0) {
      scanf("%d", &num);
      if (List == NULL) {
        p = new Node;
        p->next = NULL;
        p->last = NULL;
        p->number = num;
        List = p;
      } else {
        p = new Node;
        Node *temp = List;
        List = p;
        p->next = temp;
        p->last = temp->last;
        p->number = num;
        temp->last = p;
      }
    }
    if (strcmp(temp, "delete") == 0) {
      scanf("%d", &num);
      Node *temp = List;
      while (temp != NULL) {
        //	cout<<temp->number<<endl;
        if (temp->number == num) {
          if (temp->last == NULL) {
            List = temp->next;
            delete temp;
            break;
          }
          if (temp->next == NULL) {
            temp->last->next = NULL;
            delete temp;
            break;
          } else {
            temp->last->next = temp->next;
            temp->next->last = temp->last;
            delete temp;
            break;
          }
        } else
          temp = temp->next;
      }
    }
    if (strcmp(temp, "deleteFirst") == 0) {
      Node *temp = List;
      List = List->next;
      delete temp;
    }
    if (strcmp(temp, "deleteLast") == 0) {
      Node *temp = List;
      while (temp->next != NULL) {
        temp = temp->next;
      }
      temp->last->next = NULL;
      delete temp;
    }
  }

  while (List != NULL) {
    printf("%d", List->number);
    if (List->next != NULL)
      printf(" ");
    else {
      printf("\\n");
    }
    List = List->next;
    //	delete List->last;
  }

  return 0;
}