/*QUE: 100 people standing in a circle in an order 1 to 100. No. 1 has a sword. He kills the next person (i.e. No. 2) and gives the sword to the next (i.e. No. 3). All people do the same until only 1 survives. Which number survives at the last? 

There are 100 people starting from 1 to 100. */

​

​

​

using System;

using System.Linq;

​

public class Program

{

    // Driver code

    static public void Main ()

    {

        int person = 200;

        // Placeholder array for person

        int[] a = new int[person];

        // Assign placeholders from 1 to N (total person)

        for (int i = 0; i < person; i++) {

            a[i] = i + 1;

        }

        // Will start the game from 1st person (Which is at

        // placeholder 0)

        int pos = 0;

        // Game will be continued till we end up with only one

        // person left

        while (a.Length > 1)

        {

            // Current person will shoot the person next to

            // him/her. So incrementing the position.

            pos++;

            // As person are standing in circular manner, for

            // person at last place has right neighbour at

            // placeholder 0. So we are taking modulo to make it

            // circular

            pos %= a.Length;

            // Killing the person at placeholder 'pos'

            // To do that we simply remove that element

            a = a.Where((source, index) =>index != pos).ToArray();

            // There is no need to increment the pos again to

            // pass the gun Because by erasing the element at

            // 'pos', now next person will be at 'pos'.

        }

        // Print Person that survive the game

        Console.Write(a[0]);

    }

}