public static int GetValueIntAtv1(Node head, int idx)
{
if (head == null)
{
throw new ArgumentNullException("Head not found.");
}
if (idx < 0)
{
throw new ArgumentOutOfRangeException("Invalid index.");
}
int listLength = LinkedListHelper.GetLinkedListLength(head);
if (idx > listLength)
{
throw new ArgumentOutOfRangeException("Index is out of range.");
}
Node ref1 = head;
Node ref2 = head;
for (int i = 0; i < idx; i++)
{
ref1 = ref1.Next;
}
while (ref1 != null)
{
ref1 = ref1.Next;
ref2 = ref2.Next;
}
return(ref2.Value);
}
public static int GetValueIntAtv2(Node head, int idx)
{
if (head == null)
{
throw new ArgumentNullException("Head not found.");
}
if (idx < 0)
{
throw new ArgumentOutOfRangeException("Invalid index.");
}
int listLength = LinkedListHelper.GetLinkedListLength(head);
if (idx > listLength)
{
throw new ArgumentOutOfRangeException("Index is out of range.");
}
Node iterator = head;
int count = listLength - idx;
for (int i = 0; i < count; i++)
{
iterator = iterator.Next;
}
return(iterator.Value);
}
public static Node IsCircle(Node head)
{
Node iterator = head;
if (iterator == null)
{
return(null);
}
int idx = 0;
int length = LinkedListHelper.GetLinkedListLength(head);
int[] buffer = new int[length];
while (iterator != null)
{
if (!buffer.Contains(iterator.Value))
{
buffer[idx] = iterator.Value;
idx++;
}
else
{
return(iterator);
}
iterator = iterator.Next;
}
return(null);
}
public static bool IsPalindrome_v2(Node head)
{
Node iterator = head;
if (iterator == null)
{
throw new ArgumentNullException("Head not found.");
}
int length = LinkedListHelper.GetLinkedListLength(head);
int idx = 0, endIdx = 0, startIdx = 0;
int[] buffer;
bool isEven = length % 2 == 0;
bool isPalindome = true;
if (isEven)
{
buffer = new int[length / 2 - 1];
endIdx = length / 2 - 1;
startIdx = length / 2;
}
else
{
buffer = new int[(length - 1) / 2 - 1];
endIdx = (length - 1) / 2 - 1;
startIdx = (length - 1) / 2 + 1;
}
while (iterator != null)
{
if (idx <= endIdx)
{
buffer[idx] = iterator.Value;
idx++;
}
else if (idx >= startIdx)
{
idx--;
if (buffer[idx] != iterator.Value)
{
return(false);
}
}
else
{
idx++;
}
iterator = iterator.Next;
}
return(isPalindome);
}
public static Node GetIntersection(Node list1, Node list2)
{
if (list1 == null || list2 == null)
{
return(null);
}
int length1 = LinkedListHelper.GetLinkedListLength(list1);
int length2 = LinkedListHelper.GetLinkedListLength(list2);
Node iterator1 = length1 <= length2 ? list1 : list2;
Node iterator2 = length1 <= length2 ? list2 : list1;
Node result = null;
Node iterator3 = result;
while (iterator1 != null)
{
iterator2 = list2;
while (iterator2 != null)
{
if (iterator1.Value == iterator2.Value)
{
if (iterator3 == null)
{
iterator3 = new Node(iterator1.Value);
result = iterator3;
}
else
{
iterator3.Next = new Node(iterator1.Value);
iterator3 = iterator3.Next;
}
iterator2 = iterator2.Next;
list1 = iterator1;
list2 = iterator2;
break;
}
else
{
if (result != null)
{
return(result);
}
}
iterator2 = iterator2.Next;
}
iterator1 = iterator1.Next;
}
return(result);
}
public static Node Addition2_v2(Node h1, Node h2)
{
int val1 = 0, val2 = 0;
int idx = LinkedListHelper.GetLinkedListLength(h1) - 1;
while (h1 != null)
{
val1 += h1.Value * (int)Math.Pow(10, idx);
idx--;
}
idx = LinkedListHelper.GetLinkedListLength(h2) - 1;
while (h2 != null)
{
val2 += h2.Value * (int)Math.Pow(10, idx);
idx--;
}
string result = (val1 + val2).ToString();
Node headRes = null;
Node iterator = headRes;
for (int i = 0; i < result.Length; i++)
{
if (headRes == null)
{
headRes = new Node(result[i]);
}
else
{
iterator.Next = new Node(result[i]);
iterator = iterator.Next;
}
}
return(headRes);
}
public static bool IsPalindrome_v1(Node head)
{
if (head == null || head.Next == null)
{
return(false);
}
Node iterator = head;
int linkedListLength = LinkedListHelper.GetLinkedListLength(head);
//Stack<int> intStack = new Stack<int>();
int[] intStack = new int[linkedListLength / 2];
int count = 0, i = -1;
bool paired = linkedListLength % 2 == 0;
if (paired)
{
while (iterator != null)
{
if (count >= linkedListLength / 2)
{
if (intStack[i] != iterator.Value)
{
return(false);
}
i--;
}
else
{
intStack[count] = iterator.Value;
count++;
i++;
}
iterator = iterator.Next;
}
return(true);
}
else
{
bool first = true;
while (iterator != null)
{
if (count >= linkedListLength / 2)
{
if (first)
{
first = false;
}
else
{
if (intStack[i] != iterator.Value)
{
return(false);
}
i--;
}
}
else
{
intStack[count] = iterator.Value;
count++;
i++;
}
iterator = iterator.Next;
}
return(true);
}
}
