AC!

2023202/main.cpp

@@ -1,121 +1,47 @@
 #include <stdio.h>
 
-template <class E> class Node {
-private:
-    E content;
-    Node<E> *next;
-
-public:
-    Node(const E &_content) : content(_content), next(this){};
-    Node(const E &_content, Node<E> *nextPtr)
-        : content(_content), next(nextPtr){};
-    void setNext(Node<E> *_ptr) {
-        this->next = _ptr;
-    }
-    E &getContent() {
-        return this->content;
-    }
-    Node<E> *getNextPtr() {
-        return this->next;
-    }
+struct Node{
+    int prev, next;
 };
 
-template <class E> class Iterator {
-private:
-    Node<E> *current;
-
-public:
-    Iterator(Node<E> *start) : current(start){};
-    E &peekNext() {
-        return this->current->getNextPtr()->getContent();
-    }
-    void next() {
-        this->current = this->current->getNextPtr();
-    }
-    E &peek() {
-        return this->current->getContent();
-    }
-    Node<E> *peekNode() {
-        return this->current;
-    }
-    void insertHere(const E &newItem) {
-        this->current->setNext(
-            new Node<E>(newItem, this->current->getNextPtr()));
-    }
-};
-
-template <class E> class List {
-private:
-    // int _length;
-    Node<E> head;
-
-public:
-    List(const E &dummyValue)
-        : head(Node<E>(dummyValue)){
-              // this->_length = 0;
-          };
-    void insert(const E &target, const E &newItem) {
-        Iterator<E> iter = Iterator<E>(&this->head);
-        // Remember to add a loop to stop at length!!;
-        while (iter.peek() != target) {
-            iter.next();
-        }
-        iter.insertHere(newItem);
-        // this->_length++;
-    }
-    void remove(const E &target) {
-        Iterator<E> iter = Iterator<E>(&this->head);
-        while (iter.peekNext() != target) {
-            iter.next();
-        }
-        Node<E> *toBeDeleted = iter.peekNode()->getNextPtr();
-        iter.peekNode()->setNext(toBeDeleted->getNextPtr());
-        delete toBeDeleted;
-        // this->_length--;
-    }
-    Iterator<E> iterate() {
-        return Iterator<E>(&this->head);
-    }
-};
+Node map[100000];
 
 int main() {
-    List<int> aList(0);
-    aList.insert(0, 1);
+    map[0].prev = 1;
+    map[0].next = 1;
+    map[1].prev = 0;
+    map[1].next = 0;
     int n;
     int cmd, x, y;
     scanf("%d", &n);
     while (n) {
         scanf("%d %d", &cmd, &x);
-        switch (cmd) {
-        case 1: {
-            scanf("%d", &y);
-            aList.insert(x, y);
-            break;
-        }
-        case 2: {
-            Iterator<int> iter = aList.iterate();
-            while (iter.peek() != x) {
-                iter.next();
+        switch(cmd) {
+            case 1: {
+                scanf("%d", &y);
+                map[y].prev = x;
+                map[y].next = map[x].next;
+                map[x].next = y;
+                map[map[y].next].prev = y;
+                break;
+            }
+            case 2: {
+                printf("%d\n", map[x].next);
+                break;
+            }
+            case 3: {
+                map[map[x].prev].next = map[x].next;
+                map[map[x].next].prev = map[x].prev;
+                break;
             }
-            printf("%d\n", iter.peekNext());
-            break;
-        }
-        case 3: {
-            aList.remove(x);
-        }
         }
         n--;
     }
 
-    Iterator<int> iter = aList.iterate();
-    iter.next();
-    while (true) {
-        int content = iter.peek();
-        if (content == 0) {
-            break;
-        }
-        printf("%d\n", content);
-        iter.next();
+    int cur = map[0].next;
+    while (cur != 0) {
+        printf("%d\n", cur);
+        cur = map[cur].next;
     }
     return 0;
 }