private static int Partition(IComparable[] a, int lo, int hi)
{
int i = lo, j = hi + 1;
IComparable v = a[lo];
while (true)
{
while (SortHelper.Less(a[++i], v))
{
if (i == hi)
{
break;
}
}
while (SortHelper.Less(v, a[--j]))
{
if (j == lo)
{
break;
}
}
if (i >= j)
{
break;
}
SortHelper.Exchange(a, i, j);
}
SortHelper.Exchange(a, lo, j);
return(j);
}
private static int Partition <Key>(Key[] a, IComparer <Key> c, int lo, int hi) where Key : class
{
int i = lo, j = hi + 1;
Key v = a[lo];
while (true)
{
while (SortHelper.Less(c, a[++i], v))
{
if (i == hi)
{
break;
}
}
while (SortHelper.Less(c, v, a[--j]))
{
if (j == lo)
{
break;
}
}
if (i >= j)
{
break;
}
SortHelper.Exchange(a, i, j);
}
SortHelper.Exchange(a, lo, j);
return(j);
}
public void SelectTest()
{
String[] a = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
Shuffle.Do(a);
String v = QuickSelect.Select(a, 3) as String;
Assert.IsNotNull(v);
Assert.AreEqual("3", v);
for (int i = 0; i < 3; i++)
{
Assert.IsTrue(SortHelper.Less(a[i], v));
}
Assert.AreEqual(a[3], v);
}
public void SelectWithComparerTest()
{
Point[] points = new Point[10];
for (int i = 0; i < 10; i++)
{
points[i] = new Point(i, 10 - i);
}
Shuffle.Do(points);
Point v = QuickSelect.Select(points, Point.X_ORDER, 3) as Point;
Assert.IsNotNull(v);
Assert.AreEqual(3, v.X);
Assert.AreEqual(7, v.Y);
for (int i = 0; i < 3; i++)
{
Assert.IsTrue(SortHelper.Less(Point.X_ORDER, points[i], v));
}
Assert.AreEqual(points[3], v);
}
