import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;


public class Search {
	private static int NUM_SAMPLES = 1000;

	public static void main(String[] args) {		
		Scanner console = new Scanner(System.in);
		System.out.print("How many numbers do you want to use? ");
		int n = console.nextInt();

		// warm-up
		for (int i = 0; i < 100; i++) {
			linearSearch(new int[3*n], 1);
		}

		// run the three timed tests
		double time1 = test(n);
		double time2 = test(2 * n);
		double time3 = test(3 * n);

		System.out.println("Double/single ratio = " + time2 / time1);
		System.out.println("Triple/single ratio = " + time3 / time1);		
	}

	public static double test(int n) {
		int[] nums = generateArray(n);
		Arrays.sort(nums);

		double sum = 0;
		for (int i = 0; i < NUM_SAMPLES; i++) {
			long startTime = System.nanoTime();
			linearSearch(nums, 1);
			sum += System.nanoTime() - startTime;
		}
		double elapsed = sum / NUM_SAMPLES;


		// report and return results
		System.out.println("for n = " + n + ", time = " + elapsed);
		System.out.println();
		return elapsed;
	}

	public static int binarySearch(int[] nums, int value) {
		return binarySearch(nums, value, 0, nums.length - 1);		
	}

	private static int binarySearch(int[] nums, int value, int min, int max) {
		if (min > max) {
			return -1;
		}

		int mid = (min + max) / 2;
		if (nums[mid] == value) {
			return mid;
		} else if (nums[mid] > value) {
			return binarySearch(nums, value, min, mid - 1);
		} else { // nums[mid] < value
			return binarySearch(nums, value, mid + 1, max);
		}
	}

	public static int linearSearch(int[] nums, int value) {
		for (int i = 0; i < nums.length; i++) {
			if (nums[i] == value) {
				return i;
			}
		}

		return -1;
	}

	public static int[] generateArray(int n) {
		Random rand = new Random();
		int[] nums = new int[n];
		for (int i = 0; i < n; i++) {
			nums[i] = rand.nextInt() % (n * 10);
		}		

		return nums;
	}
}