void sumLinks(Node* list1, Node* list2) {
if (list1 == NULL && list2 == NULL) return;
int carry = 0;
int val = 0;
Node* l1 = list1;
Node* l2 = list2;
/// determine if a list is longer and if so, pad that list
int l1Len = lenList(l1);
int l2Len = lenList(l2);
if (l1Len > l2Len) {
padList(l2, l1Len - l2Len);
}
if (l2Len > l1Len) {
padList(l1, l2Len - l1Len);
}
while (l1 || l2) {
l1->data += carry;
val = l1->data + l2->data;
if (val > 9) {
carry = 1;
val = val - 10;
}
else {
carry = 0;
}
l1->data = val;
l1 = l1->next;
l2 = l2->next;
}
/// if the final digit had a carry we need to add one to the end
if (carry) {
/// reset the head and find the last element
l1 = list1;
while (l1->next) {
l1 = l1->next;
}
l1->next = new Node();
l1->next->data = 1;
l1->next->next = nullptr;
}
}
ListNode* rotateRight(ListNode* head, int k) {
if (head == nullptr) return head;
int n = lenList(head);
k = (n - k % n) % n;
ListNode** prev = &head;
for (int i = 0; i < k; i++) {
prev = &(*prev)->next;
}
ListNode* new_head = *prev;
*prev = nullptr;
for (ListNode* i = new_head; i != nullptr; i = i->next) {
prev = &i->next;
}
*prev = head;
return new_head;
}
ListNode* reverseKGroup(ListNode* head, int k) {
ListNode* resHead = NULL;
ListNode** tail = &resHead;
int len = lenList(head);
while (len >= k) {
ListNode** nextTail = &head->next;
for (int i = 0; i < k; i++) {
auto next = head->next;
head->next = *tail;
*tail = head;
head = next;
}
len -= k;
tail = nextTail;
}
*tail = head;
return resHead;
}
int ll::lenList(node *curr,int len){
if(!curr) return len;
curr=curr->next;
return lenList(curr,len+1);
}
