public NodeLL SwapPairs(NodeLL head)
{
if (head == null || head.next == null)
{
return(head);
}
NodeLL node = head;
head = node.next; // remember head node;
NodeLL prevNode = null;
while (node != null)
{
NodeLL nextPair = null;
if (node.next != null)
{
nextPair = node.next.next; // remember next pair start
node = SwapPair(node); // swap current pair
}
if (prevNode != null)
{
prevNode.next = node; // link prev pair to current
}
prevNode = node.next; // remember current pair end
node = nextPair;
}
return(head);
}
NodeLL SwapPair(NodeLL node)
{
// assume node!=null and node.next!=null
NodeLL nextNode = node.next; // node 2
NodeLL nextNextNode = nextNode.next; // node 3
node.next = nextNextNode; //link node 1 to 3
nextNode.next = node; // link node 2 to 1
return(nextNode); // return node 2
}
public NodeLL Swap(NodeLL head)
{
NodeLL node = head;
NodeLL nextNode = node.next;
NodeLL nextnextNode = nextNode.next;
node.next = nextnextNode;
nextNode.next = node;
return(nextNode);
}
public NodeLL MergeK(NodeLL [] list)
{
NodeLL ptr = new NodeLL(0);
NodeLL res = ptr;
for (int i = 0; i < list.Length; i++)
{
ptr = Merge(ptr, list[i]);
}
return(ptr);
}
public NodeLL ReverseKPairs(NodeLL head, int k)
{
int count = 0;
NodeLL current = head;
NodeLL next = null;
NodeLL prev = null;
while (current != null && count < k)
{
next = current.next;
current.next = prev;
prev = current;
current = next;
count++;
}
if (next != null)
{
head.next = ReverseKPairs(next, k);
}
return(prev);
}
public NodeLL Merge(NodeLL l1, NodeLL l2)
{
NodeLL ptr = new NodeLL(0);
NodeLL head = ptr;
while (l1 != null && l2 != null)
{
if (l1.data < l2.data)
{
ptr.next = new NodeLL(l1.data);
l1 = l1.next;
}
else
{
ptr.next = new NodeLL(l2.data);
l2 = l2.next;
}
ptr = ptr.next;
}
ptr.next = l1 != null ? l1 : l2;
return(head.next);
}
public NodeLL Merge(NodeLL ptr, NodeLL l1)
{
NodeLL res = new NodeLL(0);
NodeLL head = res;
while (ptr != null && l1 != null)
{
if (ptr.data < l1.data)
{
res = new NodeLL(ptr.data);
ptr = ptr.next;
}
else
{
res = new NodeLL(l1.data);
l1 = l1.next;
}
res = res.next;
}
res.next = l1 != null ? l1 : ptr;
return(head.next);
}
public NodeLL SwapPairs(NodeLL head)
{
NodeLL node = head;
head = node.next;
NodeLL prev = null;
while (head != null)
{
NodeLL nextPair = null;
if (node.next != null)
{
nextPair = node.next.next;
node = Swap(head);
}
if (prev != null)
{
prev.next = node;
}
prev = node.next;
node = nextPair;
}
return(head);
}
static void Main(string[] args)
{
//string s = "babad";
//MS1 m = new MS1();
//string res = m.longestPalindrome(s);
// string s = "-42";
// MS2 m = new MS2();
//long res= m.SToI(s);
//string s = "VIII";
// MS3 n = new MS3();
//n.RomanToInt(s);
//MS4 m = new MS4();
//int[] arr = { -1, 0, 1, 2, -1, -4 };
//List<List<int>> l=m.ThreeSum(arr);
//SortColors s = new SortColors();
//int[] arr = { 2, 0, 2, 1, 1, 0 };
//int []arr1=s.Sort(arr);
//validParenthesis v = new validParenthesis();
//string s = "{ ]";
//bool res=v.IsValid1(s);
NodeLL n = new NodeLL(1);
n.next = new NodeLL(2);
n.next.next = new NodeLL(3);
n.next.next.next = new NodeLL(4);
n.next.next.next.next = new NodeLL(5);
//NodeLL m = new NodeLL(1);
//m.next = new NodeLL(3);
//m.next.next = new NodeLL(4);
//NodeLL[] l = { n, m };
//MS6 p = new MS6();
//MS7 m = new MS7();
//NodeLL l=m.SwapPairs(n);
//MS8 m = new MS8();
//NodeLL res=m.ReverseKPairs(n, 2);
//MS9 m1 = new MS9();
//int[] arr = { 0, 0, 1, 1, 1, 2, 2, 3, 3, 4 };
//int l = m1.RemoveDuplicates(arr);
//string hay = "hello";
//string needle = "ll";
//MS10 m = new MS10();
//int res=m.StrStr(hay, needle);
//MS11 m = new MS11();
//int[] arr = { 4, 5, 1, 2, 3 };
//int res=m.Search(arr, 3);
//MS12 p = new MS12();
//int[] arr = { 1, 1, 3 };
//List<List<int>> p2=p.Permutation(arr);
//MS13 m = new MS13();
//string s = "my name is parvathi";
//string res=m.Rotate(s);
//Trie o = new Trie();
//string s = "leet";
//o.Insert(s);
//bool res1 = o.Search(s);
//bool res2 = o.StartsWith("lee");
char[,] board = { { 'o', 'a', 'a', 'n' }, { 'e', 't', 'a', 'e' },
{ 'i', 'h', 'k', 'r' },
{ 'i', 'f', 'l', 'v' } };
string[] words = { "oath", "pea", "eat", "rain" };
TrieWordSearch t = new TrieWordSearch();
List <string> res = t.FindWords(board, words);
}