package algs14;
import stdlib.*;
public class XCountingString {  
  // Test variants that resize additively or multiplicatively
  // int capacity = 1 + a.length;
  // int capacity = 2 * a.length;
  // int capacity = (int)Math.ceil(1.5 * a.length);
  private static char[] resize (char[] a) {
    int capacity = 2 * a.length;
    char[] result = new char[capacity]; 
    for (int i = 0; i < a.length; i = i + 1) {
      result[i] = a[i];
      numOps = numOps + 1;
    }
    return result;
  }
  // f creates a string of length N, counting the total size of all strings created
  public static String f (long N) {
    char[] a = new char[1];
    for (int i = 0; i < N; i = i + 1) {
      if (i >= a.length) 
        a = resize(a);
      a[i] = '*';
      numOps = numOps + 1;
    }   
    return String.valueOf(a); // creates a string in linear time
  }
  private static long numOps;
  public static void main (String[] args) {
    long MIN = 500L;
    long MAX = 3200000L;
    Stopwatch sw = new Stopwatch ();
    numOps = 0;
    f(MIN);
    double prevCount = numOps;
    double prevTime = sw.elapsedTime ();
    for (long N = MIN*2; N <= MAX; N=N*2) {
      sw = new Stopwatch ();
      numOps = 0;
      f(N);
      long count = numOps; 
      double time = sw.elapsedTime ();
      StdOut.format ("Elapsed count f(%,13d): %,17d: %10.3f [%10.3f : %10.3f]\n", N, count, count / prevCount, time, time/prevTime);
      //StdOut.format ("Elapsed count f(%,13d): %,17d: %10.3f\n", N, count, count / prevCount);
      prevCount = count;
      prevTime = time;
    }
  }
}