using System;
using System.Linq;
using System.Collections.Generic;
using System.Threading;
public class Test
{
	public class DataPoint {
		public double X {get; set;}
		public double Y {get; set;}
	}
	public static void Main()
	{
		int count = 39;
		// generate our points
		List<DataPoint>[] sets = new List<DataPoint>[count];
		double[] result = new double[count];
		for(var i=0; i<sets.Length; i++) { 
			sets[i] = GetRandomDataPoints(200); 
		}
		// run our calculations async
		int running = count;
		using(ManualResetEvent resetEvent = new ManualResetEvent(false)){
	    	for(int i=0; i<count; i++) {
	    		int idx = i;
        		ThreadPool.QueueUserWorkItem(
           			new WaitCallback(o => {
           				result[idx] = GetAbsoluteMax(sets[idx]);
			            if (Interlocked.Decrement(ref running) == 0) {
           					resetEvent.Set();
			            }
           			}),
           			null
           		);
	    	}
    		resetEvent.WaitOne();
		}
		foreach(var max in result) {
			Console.WriteLine(max);
		}
	}
	public static double GetAbsoluteMax(List<DataPoint> list) {
    	double max = 0;
    	// calc dist for each distinct pair Dist(P_1, P_2) == Dist(P_2, P_1)
    	for(var i=0; i<list.Count-1; i++) {
    		for(var j=i+1; j<list.Count; j++) {
    			var dX = list[i].X - list[j].X;
    			var dY = list[i].Y - list[j].Y;
    			// don't calculate the Square Root yet
    			var dist = dX * dX + dY * dY;
    			if(dist > max) {
    				max = dist;
    			}
    		}
    	}
    	return Math.Sqrt(max);
	}
	public static List<DataPoint> GetRandomDataPoints(int size) {
		var result = new List<DataPoint>();
		var rnd = new Random();
		for(var i=0; i<size; i++) {
			result.Add(new DataPoint() { 
				X=rnd.NextDouble()*100, 
				Y=rnd.NextDouble()*100 
				});
		}
		return result;
	}
}