RosettaCodeData/Task/Longest-increasing-subsequence/C-sharp/longest-increasing-subseque...

23 lines
904 B
C#

public static class LIS
{
public static T[] Find<T>(IList<T> values, IComparer<T> comparer = null) {
if (values == null) throw new ArgumentNullException();
if (comparer == null) comparer = Comparer<T>.Default;
var pileTops = new List<T>();
var pileAssignments = new int[values.Count];
for (int i = 0; i < values.Count; i++) {
T element = values[i];
int pile = pileTops.BinarySearch(element, comparer);
if (pile < 0) pile = ~pile;
if (pile == pileTops.Count) pileTops.Add(element);
else pileTops[pile] = element;
pileAssignments[i] = pile;
}
T[] result = new T[pileTops.Count];
for (int i = pileAssignments.Length - 1, p = pileTops.Count - 1; p >= 0; i--) {
if (pileAssignments[i] == p) result[p--] = values[i];
}
return result;
}
}