/// <summary>
/// For an array of monotonically increasing values, returns
/// the index i of the largest value such that array[i] <= x.
/// If x is smaller than the first value, then -1 is returned.
/// If x is greater than the last value, then a.Length is returned.
/// </summary>
public static long LongIndexOfLargestLessOrEqual <T>(this T[] a, T x)
where T : IComparable
{
var r = new Range1l(0, a.Length - 1);
if (x.CompareTo(a[0]) < 0)
{
return(-1);
}
if (x.CompareTo(a[r.Max]) > 0)
{
return(a.Length);
}
while (r.Size > 1)
{
var half = r.Center;
if (x.CompareTo(a[half]) < 0)
{
r.Max = half;
}
else
{
r.Min = half;
}
}
return(r.Min);
}
public void Write(Range1l x)
{
Write(x.Min); Write(x.Max);
}
