struct ListNode *getIntersectionNode(struct ListNode *headA, struct ListNode *headB) {
int Len1, Len2, i;
if (headA == NULL || headB == NULL)
return NULL;
Len1 = GetLengthOfList(headA);
Len2 = GetLengthOfList(headB);
if (Len1 > Len2)
{
for (i = 0; i < Len1 - Len2; ++i)
headA = headA -> next;
}
if (Len2 > Len1)
{
for (i = 0; i < Len2 - Len1; ++i)
headB = headB -> next;
}
while (headA != NULL)
{
if (headA -> val == headB -> val)
return headA;
headA = headA -> next;
headB = headB -> next;
}
return NULL;
}
ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
if(pHead1==nullptr || pHead2==nullptr){
return nullptr;
}
unsigned int len1 = GetLengthOfList(pHead1);
unsigned int len2 = GetLengthOfList(pHead2);
int lengthDiff = len1-len2;
ListNode* pListHeadLong = pHead1;
ListNode* pListHeadShort = pHead2;
if(len2>len1){
pListHeadLong = pHead2;
pListHeadShort = pHead1;
lengthDiff = len2-len1;
}
for(int i=0;i<lengthDiff;i++){
pListHeadLong=pListHeadLong->next;
}
while(pListHeadLong!=nullptr && pListHeadShort!=nullptr){
if(pListHeadLong==pListHeadShort){
break;
}else{
pListHeadLong=pListHeadLong->next;
pListHeadShort=pListHeadShort->next;
}
}
return pListHeadLong;
}
struct ListNode* reverseKGroup(struct ListNode* head, int k) {
if (k <= 1 || head == NULL || head -> next == NULL)
return head;
int RoundOfReverse, Len;
int i, j;
List NewList;
Position PtrBeforeEnd, PtrSubBegin, PtrPre, PtrCur, PtrNext;
Len = GetLengthOfList(head);
if (Len < k)
return head;
RoundOfReverse = Len / k;
PtrPre = head;
PtrCur = head -> next;
for (i = 0; i < RoundOfReverse; ++i)
{
PtrSubBegin = PtrPre;
for (j = 1; j < k; ++j)
{
PtrNext = PtrCur -> next;
PtrCur -> next = PtrPre;
PtrPre = PtrCur;
PtrCur = PtrNext;
}
if (i == 0)
NewList = PtrPre;
else
{
PtrBeforeEnd -> next = PtrPre;
}
PtrSubBegin -> next = PtrCur;
PtrBeforeEnd = PtrSubBegin;
PtrPre = PtrCur;
if (PtrCur != NULL)
PtrCur = PtrCur -> next;
}
return NewList;
}
