package rebelsky.exam4;

import java.math.BigInteger;
import java.util.Random;
import java.util.Vector;

public class VectorUtils
{
  public static <T> Vector<T> duplicate(Vector<T> vec)
  {
    int len = vec.size();
    Vector<T> result = new Vector<T>(len);
    for (int i = 0; i < len; i++) {
      result.add(vec.get(i));
    }
    return result;
  } // duplicate(Vector<T>)

  public static Vector<BigInteger> randomSortedVector(int n)
  {
    Random rand = new Random();
    Vector<BigInteger> result = new Vector<BigInteger>(n);
    BigInteger val = BigInteger.valueOf(rand.nextInt());
    for (int i = 0; i < n; i++) {
      val = val.add(BigInteger.valueOf(Math.abs(rand.nextInt()) % 5));
      result.add(val);
    } // for
    return result;
  } // randomSortedVector(int)

  public static <T> void permute(Vector<T> v) 
  {
    Random rand = new Random();
    // Our permutation is fairly simple: We swap each element with a
    // "randomly" chosen element.
    int len = v.size();
    for (int i = 0; i < v.size(); i++) {
      swap(v, i, Math.abs(rand.nextInt()) % len);
    } // for
  } // permute(Vector<T>)

  public static <T> void swap(Vector<T> v, int a, int b)
  {
    T tmp = v.get(a);
    v.set(a, v.get(b));
    v.set(b, tmp);
  } // swap
} // class VectorHelper