ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
// if two linked lists have intersection, thay share the same tail-node.
if (headA == NULL || headB == NULL) {
return NULL;
}
ListNode *tailA = headA;
int lenA = moveToTail(tailA);
ListNode *tailB = headB;
int lenB = moveToTail(tailB);
if (lenA > lenB) {
headA = move(headA, lenA - lenB);
}
else {
headB = move(headB, lenB - lenA);
}
while (headA != headB) {
headA = headA->next;
headB = headB->next;
}
return headA;
}
//default need to be implemented
int get(int key) {
if(hash.find(key) == hash.end()){//not in the hash table
return -1;
}
else{
cacheNode* cur = hash[key];
//remove the node from cur position, and move to the tail
cur->prev->next = cur->next;
cur->next->prev = cur->prev;
moveToTail(cur);
return cur->val;
}
}
//default need to be implemented
void set(int key, int value) {
//if(hash.find(key) != hash.end()){
//hash[key]->val = value; //update
//hash[key]->prev->next = hash[key]->next;//delete the node from cur position
//hash[key]->next->prev = hash[key]->prev;
//moveToTail(hash[key]); //move to tail
//}
if(get(key) != -1){//if the node with the same key already in the cache
hash[key]->val = value;
return;
}
else{
if(hash.size() == capacity){
hash.erase(head->next->key); //added a cacheNode(0, 0) as head
head->next = head->next->next;
head->next->prev = head;
}
cacheNode* node = new cacheNode(key, value);
hash[key] = node;
moveToTail(node);
}
}