The function ch_eddy generates the counterclockwise sequence of extreme points from a given set of input points.
generates the counterclockwise sequence of extreme points
of the points in the range [first,beyond).
The resulting sequence is placed starting at position
result, and the past-the-end iterator for the resulting
sequence is returned. It is not specified at which point the
cyclic sequence of extreme points is cut into a linear sequence.
The default traits class Default_traits is the kernel in which the type ForwardIterator::value_type is defined.
This function implements Eddy's algorithm [Edd77], which is the two-dimensional version of the quickhull algorithm [BDH96] . This algorithm requires O(n h) time in the worst case for n input points with h extreme points.