/**
 * Created by Xan Gregg.
 * Date: Jan 12, 2006
 */
public class TestRangeCheck {
    public static final int M = 5000;
    public static final int N = 10000;

    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {
            time(new Easy());
            time(new Medium());
            time(new Hard());
            time(new HardWithHint());
            System.out.println();
        }
    }

    private static void time(Worker w) {
        long start = System.currentTimeMillis();
        double result = w.work();
        long end = System.currentTimeMillis();
        long elapsed = end - start;
        System.out.println(w.getClass().getName() + "  result = " + result + "; elapsed = " + elapsed);
    }

    interface Worker {
        double work();
    }


    static class Easy implements Worker {
        double data[] = new double[N];

        public double work() {
            for (int i = 0; i < N; i++) {
                int j = i;                      // same as i
                int k = i / 2 + (i + 1) / 2;    // same as i
                data[i] = j - k;
            }
            double sum = 0;
            for (int m = 0; m < M; m++) {
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    data[i] += 1.0 / ((m * N + j) * 2 + 1) * -((k % 2) * 2 - 1);
                }
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    sum += data[i] + k - j;
                }
            }
            return sum * 4 / M;
        }
    }

    static class Medium implements Worker {
        double data[] = new double[N];

        public double work() {
            for (int i = 0; i < N; i++) {
                int j = i;                      // same as i
                int k = i / 2 + (i + 1) / 2;    // same as i
                data[j] = j - k;
            }
            double sum = 0;
            for (int m = 0; m < M; m++) {
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    data[j] += 1.0 / ((m * N + j) * 2 + 1) * -((k % 2) * 2 - 1);
                }
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    sum += data[j] + k - j;
                }
            }
            return sum * 4 / M;
        }
    }

    static class Hard implements Worker {
        double data[] = new double[N];

        public double work() {
            for (int i = 0; i < N; i++) {
                int j = i;                      // same as i
                int k = i / 2 + (i + 1) / 2;    // same as i
                data[k] = j - k;
            }
            double sum = 0;
            for (int m = 0; m < M; m++) {
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    data[k] += 1.0 / ((m * N + j) * 2 + 1) * -((k % 2) * 2 - 1);
                }
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    sum += data[k] + k - j;
                }
            }
            return sum * 4 / M;
        }
    }

    static class HardWithHint implements Worker {
        double data[] = new double[N];

        public double work() {
            for (int i = 0; i < N; i++) {
                int j = i;                      // same as i
                int k = i / 2 + (i + 1) / 2;    // same as i
                if (k >= 0 && k < data.length)
                    data[k] = j - k;
            }
            double sum = 0;
            for (int m = 0; m < M; m++) {
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    if (k >= 0 && k < data.length)
                        data[k] += 1.0 / ((m * N + j) * 2 + 1) * -((k % 2) * 2 - 1);
                }
                for (int i = 0; i < N; i++) {
                    int j = i;                      // same as i
                    int k = i / 2 + (i + 1) / 2;    // same as i
                    if (k >= 0 && k < data.length)
                        sum += data[k] + k - j;
                }
            }
            return sum * 4 / M;
        }
    }


}