Main.java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		runTests();
	}
	
	
	/**
	 * 
	 */
	public static void runTests() {
		System.out.println("For 1,000 points: ");
		PointList p1 = readFile(1000);
		runClosetDistanceAlgorithm(p1);
		testBrute(p1);
		System.out.println();
		
		System.out.println("For 10,000 points: ");
		PointList p2 = readFile(10000);
		runClosetDistanceAlgorithm(p2);
		testBrute(p2);
		System.out.println();
		
		System.out.println("For 100,000 points: ");
		PointList p3 = readFile(100000);
		runClosetDistanceAlgorithm(p3);
		testBrute(p3);
		System.out.println("Tests completed");
		
	}
	
	/**
	 * Reads the CSV file, creating a MyPoint instance for each coordinate it reads and adding each of
	 * these MyPoints to a PointList
	 * @return PointList with all points read
	 */
	public static PointList readFile() {
		PointList plist = new PointList();
		
		String csvFile = "src/xy.csv";
        Scanner scanner = null;
        String csvRegex = ",";
		
        try {
        	scanner = new Scanner(new File(csvFile));
        	
        	// Read over first line
        	scanner.nextLine();
        	
        	// Read the next line while there is a next line and create new MyPoint objects for each
        	while(scanner.hasNext()) {
        		String s = scanner.nextLine();
        		String[] values = s.split(csvRegex);
        		double xVal = Double.parseDouble(values[0]);
        		double yVal = Double.parseDouble(values[1]);
        		MyPoint p = new MyPoint(xVal, yVal);
        		plist.add(p);
        	}
        	
        	
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
		return plist;
	}
	
	/**
	 * Reads the CSV files to a desired depth. Used mostly for comparing run times of the 2 algorithms used
	 * @param depth at which file reading will stop
	 * @return PointList with all points up to depth read
	 */
	public static PointList readFile(int depth) {
		PointList plist = new PointList();
		
		String csvFile = "src/xy.csv";
        Scanner scanner = null;
        String csvRegex = ",";
		
        try {
        	scanner = new Scanner(new File(csvFile));
        	
        	// Read over first line
        	scanner.nextLine();
        	
        	// Read the next line until specified depth is reached
        	for(int i=0; i<depth; i++) {
        		String s = scanner.nextLine();
        		String[] values = s.split(csvRegex);
        		double xVal = Double.parseDouble(values[0]);
        		double yVal = Double.parseDouble(values[1]);
        		MyPoint p = new MyPoint(xVal, yVal);
        		plist.add(p);
        	}
        	
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
		return plist;
	}
	
	/**
	 * Runs the brute force algorithm and prints the execution time
	 * @param plist to be tested
	 */
	public static void testBrute(PointList plist) {
		long tStart = System.currentTimeMillis();
		System.out.println("Result: " + PointList.getClosestDistanceBrute(plist));
		long tEnd = System.currentTimeMillis();
		long tDelta = tEnd - tStart;
		double elapsedSeconds = tDelta / 1000.0;
		System.out.println("Brute force takes " + elapsedSeconds + " seconds");
	}
	
	/**
	 * Calls parent method for divide and conquer method and prints execution time
	 * @param plist to be tested
	 */
	public static void runClosetDistanceAlgorithm(PointList plist) {
		long tStart = System.currentTimeMillis();
		System.out.println("Result: " + PointList.closestDistance(plist));
		long tEnd = System.currentTimeMillis();
		long tDelta = tEnd - tStart;
		double elapsedSeconds = tDelta / 1000.0;
		System.out.println("Divide and conquer algorithm takes " + elapsedSeconds + " seconds.");
	}
	

}