Find the element in a linked list with frequency at least N/3

// C# program to find an element with
// frequency of at least N / 3 in a
// linked list 
using System;
using System.Collections;
using System.Collections.Generic;

class GFG{
 
// Structure of a node 
// for the linked list 
class node
{
    public string i; 
    public node next = null; 
}; 
 
// Utility function to 
// create a node 
static node newnode(string s) 
{ 
    node temp = new node(); 
    temp.i = s; 
    temp.next = null; 
    return temp; 
} 
 
// Function to find and return 
// the element with frequency 
// of at least N/3 
static string Majority_in_linklist(node head) 
{ 
    
    // Candidates for 
    // being the required 
    // majority element 
    string s = "";
    string t = ""; 
     
    // Store the frequencies 
    // of the respective candidates 
    int p = 0, q = 0; 
    node ptr = null; 
 
    // Iterate all nodes 
    while (head != null)
    {
        if (s.Equals(head.i))
        {
             
            // Increase frequency 
            // of candidate s 
            p = p + 1; 
        } 
        else
        { 
            if (t.Equals(head.i))
            {
                 
                // Increase frequency 
                // of candidate t 
                q = q + 1; 
            } 
            else
            { 
                if (p == 0) 
                {
                     
                    // Set the new string as 
                    // candidate for majority 
                    s = head.i; 
                    p = 1; 
                } 
                else
                { 
                    if (q == 0)
                    {
                         
                        // Set the new string as 
                        // second candidate 
                        // for majority 
                        t = head.i; 
                        q = 1; 
                    } 
                    else
                    {
                         
                        // Decrease the frequency 
                        p = p - 1; 
                        q = q - 1; 
                    } 
                } 
            } 
        } 
        head = head.next; 
    } 
    head = ptr; 
    p = 0; 
    q = 0; 
 
    // Check the frequency of two 
    // final selected candidate linklist 
    while (head != null) 
    { 
        if (s.Equals(head.i)) 
        {
             
            // Increase the frequency 
            // of first candidate 
            p = 1; 
        } 
        else
        { 
            if (t.Equals(head.i))
            {
                 
                // Increase the frequency 
                // of second candidate 
                q = 1; 
            } 
        } 
        head = head.next; 
    } 
     
    // Return the string with 
    // higher frequency 
    if (p > q) 
    { 
        return s; 
    } 
    else
    { 
        return t; 
    } 
} 
 
// Driver Code 
public static void Main(string []arg)
{ 
    node head = newnode("geeks"); 
    head.next = newnode("geeks"); 
    head.next.next = newnode("abcd"); 
    head.next.next.next = newnode("game"); 
    head.next.next.next.next = newnode("game"); 
    head.next.next.next.next.next = newnode("knight"); 
    head.next.next.next.next.next.next = newnode("harry"); 
    head.next.next.next.next.next.next.next = newnode("geeks"); 
 
    Console.Write(Majority_in_linklist(head)); 
} 
}

// This code is contributed by pratham76