import java.util.Random;

/**
 * A class to measure the running time of all three solutions to
 * the Stock Market problem.
 * 
 * The BruteForce solution quickly slows down so you may need to
 * comment out code pertaining to this solution to compare both
 * divide-and-conquer solutions
 * 
 * Ignore the bad programming style in this file. In general, you
 * should never use magic numbers!
 * 
 * @author americachambers
 *
 */
public class StockTester {
	private static Random rnd = new Random();

	public static void printAnswer(StockInfo answer, int[] prices) {
		System.out.println("Buy stock on day " + answer.buy_index + " for " + prices[answer.buy_index]);
		System.out.println("Sell stock on day " + answer.sell_index + " for " + prices[answer.sell_index]);
		System.out.println("Total profit: " + answer.profit);
	}

	/**
	 * Populates prices array with randomly chosen prices
	 * @param array
	 */
	public static void populatePrices(int[] array) {		
		for(int i = 0; i < array.length; i++) {
			array[i] = rnd.nextInt(10000)+1;
		}
	}

	public static void main(String[] args) {
		// Consider different number of days
		int[] num_days = new int[20];
		num_days[0] = 2;
		for(int i = 1; i < num_days.length; i++){
			num_days[i] = num_days[i-1]*2;
		}

		// Instantiate the 3 algorithms we are comparing
		BruteForce bf = new BruteForce();
		Recursive rf = new Recursive();
		Transformation tf = new Transformation();
		
		// This will hold the prices for each day
		int[] prices;

		// Repeatedly call, but do not time, to force Java
		// to compile to native code (i.e. forced optimization)
		int burnIn = 50;
		prices = new int[100];
		for(int j = 0; j < burnIn; j++) {
			populatePrices(prices);
			bf.solve(prices);
			rf.solve(prices);
			tf.solve(prices);
		}
		System.out.println("Finished burn in ");

		
		// Start the actual timed trials
		// For each number of days
		// 		For 10 iterations
		// 			Randomly sample new prices
		//			Run each of the 3 algorithms
		
		long start, end;		
		long recursiveTime = 0;
		long bruteForceTime = 0;
		long transformationTime = 0;
		int timedIterations = 10;

		for(int i = 0; i < num_days.length; i++) {
			prices = new int[num_days[i]];

			for(int j = 0; j < timedIterations; j++){
				populatePrices(prices);

				start = System.nanoTime();
				bf.solve(prices);
				end = System.nanoTime();
				bruteForceTime += (end - start);

				start = System.nanoTime();
				rf.solve(prices);
				end = System.nanoTime();
				recursiveTime += (end - start);
				
				start = System.nanoTime();
				tf.solve(prices);
				end = System.nanoTime();
				transformationTime += (end - start);

				// Asserting that all methods return the same answer
				StockInfo s1 = bf.solve(prices);
				StockInfo s2 = rf.solve(prices);
				StockInfo s3 = tf.solve(prices);
				assert(s1.profit == s2.profit);	
				assert(s2.profit == s3.profit);
			}

			System.out.println("Array size: " + num_days[i]);
			System.out.println("Brute force: " + ((bruteForceTime/1000)/timedIterations) + " microseconds");
			System.out.println("Recursive: " + ((recursiveTime/1000)/timedIterations) + " microseconds");
			System.out.println("Transformed: " + ((transformationTime/1000)/timedIterations) + " microseconds");
			System.out.println();
		}
	}
}


// Results with all 3
//Finished burn in 
//Array size: 2
//Brute force: 0 microseconds
//Recursive: 4 microseconds
//Transformed: 1 microseconds
//
//Array size: 4
//Brute force: 0 microseconds
//Recursive: 8 microseconds
//Transformed: 3 microseconds
//
//Array size: 8
//Brute force: 0 microseconds
//Recursive: 15 microseconds
//Transformed: 8 microseconds
//
//Array size: 16
//Brute force: 1 microseconds
//Recursive: 27 microseconds
//Transformed: 16 microseconds
//
//Array size: 32
//Brute force: 2 microseconds
//Recursive: 51 microseconds
//Transformed: 30 microseconds
//
//Array size: 64
//Brute force: 3 microseconds
//Recursive: 102 microseconds
//Transformed: 61 microseconds
//
//Array size: 128
//Brute force: 12 microseconds
//Recursive: 234 microseconds
//Transformed: 149 microseconds
//
//Array size: 256
//Brute force: 29 microseconds
//Recursive: 393 microseconds
//Transformed: 264 microseconds
//
//Array size: 512
//Brute force: 120 microseconds
//Recursive: 435 microseconds
//Transformed: 601 microseconds
//
//Array size: 1024
//Brute force: 409 microseconds
//Recursive: 525 microseconds
//Transformed: 783 microseconds
//
//Array size: 2048
//Brute force: 1436 microseconds
//Recursive: 656 microseconds
//Transformed: 918 microseconds
//
//Array size: 4096
//Brute force: 5370 microseconds
//Recursive: 845 microseconds
//Transformed: 1316 microseconds
//
//Array size: 8192
//Brute force: 21513 microseconds
//Recursive: 1214 microseconds
//Transformed: 1660 microseconds
//
//Array size: 16384
//Brute force: 80536 microseconds
//Recursive: 1650 microseconds
//Transformed: 2491 microseconds
//
//Array size: 32768
//Brute force: 311015 microseconds
//Recursive: 2691 microseconds
//Transformed: 3989 microseconds
//
//Array size: 65536
//Brute force: 1207766 microseconds
//Recursive: 4460 microseconds
//Transformed: 7265 microseconds
//

//Comparing the sub quadratic algorithms
//Finished burn in 
//Array size: 2
//Recursive: 3 microseconds
//Transformed: 0 microseconds
//
//Array size: 4
//Recursive: 11 microseconds
//Transformed: 3 microseconds
//
//Array size: 8
//Recursive: 21 microseconds
//Transformed: 10 microseconds
//
//Array size: 16
//Recursive: 33 microseconds
//Transformed: 17 microseconds
//
//Array size: 32
//Recursive: 58 microseconds
//Transformed: 31 microseconds
//
//Array size: 64
//Recursive: 105 microseconds
//Transformed: 60 microseconds
//
//Array size: 128
//Recursive: 201 microseconds
//Transformed: 115 microseconds
//
//Array size: 256
//Recursive: 422 microseconds
//Transformed: 268 microseconds
//
//Array size: 512
//Recursive: 471 microseconds
//Transformed: 625 microseconds
//
//Array size: 1024
//Recursive: 569 microseconds
//Transformed: 876 microseconds
//
//Array size: 2048
//Recursive: 759 microseconds
//Transformed: 1127 microseconds
//
//Array size: 4096
//Recursive: 998 microseconds
//Transformed: 1634 microseconds
//
//Array size: 8192
//Recursive: 1367 microseconds
//Transformed: 2008 microseconds
//
//Array size: 16384
//Recursive: 1856 microseconds
//Transformed: 2812 microseconds
//
//Array size: 32768
//Recursive: 3723 microseconds
//Transformed: 4515 microseconds
//
//Array size: 65536
//Recursive: 7824 microseconds
//Transformed: 8735 microseconds
//
//Array size: 131072
//Recursive: 12939 microseconds
//Transformed: 15381 microseconds
//
//Array size: 262144
//Recursive: 24380 microseconds
//Transformed: 31773 microseconds
//
//Array size: 524288
//Recursive: 38318 microseconds
//Transformed: 56609 microseconds
//
//Array size: 1048576
//Recursive: 65792 microseconds
//Transformed: 110365 microseconds
//