public void MagicIndexTest()
{
int n = 20;
for (int i = 0; i < 10; i++)
{
int[] data = new int[n];
Random random = new Random();
for (int j = 0; j < data.Length; j++)
{
data[j] = random.Next(-n, n);
}
Array.Sort(data);
int actual = MagicIndexClass.MagicIndex(data);
if (actual == -1)
{
Assert.IsFalse(MagicIndexTestClass.HasMagicIndex(data, n));
}
else
{
Assert.AreEqual(data[actual], actual);
}
}
}
private static int MagicIndex(int[] data, int start, int end)
{
if (start > end)
{
return(-1);
}
int mid = start + (end - start) / 2;
if (data[mid] == mid)
{
return(mid);
}
int left = MagicIndexClass.MagicIndex(data, start, Math.Min(mid - 1, data[mid]));
if (left != -1)
{
return(left);
}
return(MagicIndexClass.MagicIndex(data, Math.Max(mid + 1, data[mid]), end));
}
public static int MagicIndex(int[] data)
{
return(MagicIndexClass.MagicIndex(data, 0, data.Length - 1));
}