public static string GetLongestSubString(string text)
{
int N = text.Length;
SuffixArray suffix = new SuffixArray(text);
string lrs = "";
for (int i = 1; i < N; i++)
{
int len = suffix.Lcp(i);
if (len > lrs.Length)
{
lrs = suffix.Select(i).Substring(0, len);
}
}
return(lrs);
}