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package algs11;
import java.util.Arrays;
import stdlib.*;

public class PlaygroundMerge {
  /* Merge a and b into a sorted result */
  public static double[] merge (double[] a, double[] b) {
    return null; //TODO: fix this
  }

  /* A main function for testing */
  public static void main (String[] args) {  
    //Trace.drawStepsOfMethod ("merge");
    //Trace.run ();
    testMerge ("11 13 15", "11 15", "13");
    testMerge ("11 13 15", "13", "11 15");
    testMerge ("11 12", "11", "12");
    testMerge ("11 12", "12", "11");
    testMerge ("11", "11", "");
    testMerge ("11", "", "11");
    testMerge ("", "", "");

    // this is an example of random testing:
    for (int numTests = 10; numTests>0; numTests--) {
      double[] a = ArrayGenerator.doubleRandom (StdRandom.uniform (10), 1000);
      double[] b = ArrayGenerator.doubleRandom (StdRandom.uniform (10), 1000);
      Arrays.sort (a);
      Arrays.sort (b);
      double[] result = new double[a.length+b.length];
      System.arraycopy (a, 0, result, 0, a.length);
      System.arraycopy (b, 0, result, a.length, b.length);
      Arrays.sort (result);
      testMerge (result, a, b);
    }
    StdOut.println ("Finished tests");
  }
  
  private static void testMerge (double[] expected, double[] a, double[] b) {
    double[] actual = merge (a, b);
    if (!Arrays.equals (expected, actual)) {
      StdOut.format ("Failed merge([%s],[%s]): Expecting (%s) Actual (%s)\n", Arrays.toString (a), Arrays.toString (b), Arrays.toString (expected), Arrays.toString (actual));
    }
  }
  private static void testMerge (String expected, String aList, String bList) {
    double[] a = doublesFromString (aList);
    double[] b = doublesFromString (bList);
    double[] actual = merge (a, b);
    if (!Arrays.equals (a, doublesFromString (aList))) {
      StdOut.format ("Failed merge([%s]): Array modified\n", aList);
    }
    if (!Arrays.equals (b, doublesFromString (bList))) {
      StdOut.format ("Failed merge([%s]): Array modified\n", bList);
    }
    double[] aExpected = doublesFromString (expected);
    if (!Arrays.equals (aExpected, actual)) {
      StdOut.format ("Failed merge([%s],[%s]): Expecting (%s) Actual (%s)\n", aList, bList, Arrays.toString (aExpected), Arrays.toString (actual));
    }
  }

  /* A utility function to create an array of doubles from a string. */
  // The string should include a list of numbers, separated by single spaces.
  private static double[] doublesFromString (String s) {
    if ("".equals (s)) return new double[0]; // empty array is a special case
    String[] nums = s.split (" ");
    double[] result = new double[nums.length];
    for (int i = nums.length - 1; i >= 0; i--) {
      try {
        result[i] = Double.parseDouble (nums[i]);
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException (String.format ("Bad argument \"%s\": could not parse \"%s\" as a double", s, nums[i]));
      }
    }
    return result;
  }
}