// Space: O(n)
// Time: O(n)
public static bool IsPalindromeRecursive <T>(Node <T> head)
where T : IEquatable <T>
{
if (head == null)
{
throw new ArgumentNullException(nameof(head));
}
var length = Question_2_2.GetListLength(head);
Node <T> tempNode;
return(IsPalindromRecursiveHelper(head, length, 0, out tempNode));
}
public static Node <T> FindIntersection <T>(Node <T> head1, Node <T> head2)
where T : IEquatable <T>
{
if (head1 == null)
{
throw new ArgumentNullException(nameof(head1));
}
if (head2 == null)
{
throw new ArgumentNullException(nameof(head2));
}
var length1 = Question_2_2.GetListLength(head1);
var length2 = Question_2_2.GetListLength(head2);
var diff = Math.Abs(length1 - length2);
var longerHead = length1 > length2 ? head1 : head2;
var shorterHead = length1 <= length2 ? head1 : head2;
for (int i = 0; i < diff; i++)
{
longerHead = longerHead.Next;
}
while (longerHead != null && shorterHead != null)
{
if (ReferenceEquals(longerHead, shorterHead))
{
return(longerHead);
}
longerHead = longerHead.Next;
shorterHead = shorterHead.Next;
}
// Depending on the use case, should consider throwing and exception here.
return(null);
}
