public static LinkedListNode isIntersect(LinkedListNode L1, LinkedListNode L2)
{
LinkedListNode intersection = new LinkedListNode();
if (!checkTail(L1, L2))
{
intersection = null;
return intersection;
}
else
{
int pointerDifference = Math.Abs(findLength(L1) - findLength(L2));
LinkedListNode longNode =
pointerDifference == 0 ? L1 : findLength(L1) > findLength(L2) ? L1 : L2;
LinkedListNode shortNode =
pointerDifference == 0 ? L2 : findLength(L1) < findLength(L2) ? L1 : L2;
LinkedListNode startingNode = pointerDifference == 0 ? L1 : returnKthNode(longNode, pointerDifference);
while (startingNode != null && shortNode != null)
{
if (startingNode == shortNode)
{
intersection = startingNode;
return intersection;
}
startingNode = startingNode.next;
shortNode = shortNode.next;
}
return null;
}
LinkedListNode returnKthNode(LinkedListNode L, int k)
{
LinkedListNode startingNode = new LinkedListNode();
while (L != null && k > 0)
{
L = L.next;
k--;
}
startingNode = L;
return startingNode;
}
bool checkTail(LinkedListNode L1, LinkedListNode L2)
{
if (findTail(L1) == findTail(L2))
{
return true;
}
return false;
}
LinkedListNode findTail(LinkedListNode L)
{
LinkedListNode Tail = new LinkedListNode();
while (L != null)
{
if (L.next == null)
{
Tail = L;
}
L = L.next;
}
return Tail;
}
int findLength(LinkedListNode L)
{
int Length = 0;
while (L != null)
{
Length++;
L = L.next;
}
return Length;
}
}