public static void longest_common_substring(SuffixAutomaton sa, char[] a, out int pos, out int len)
{
pos = 0;
len = 0;
SuffixAutomaton.Node v = sa.t0;
int l = 0;
for (int u = 0; u < a.Length; u++)
{
while (v != sa.t0 && !v.ContainsKeyNext(a[u]))
{
v = v.link;
l = v.len;
}
if (v.ContainsKeyNext(a[u]))
{
v = v.GetNext(a[u]);
l++;
}
if (l > len)
{
len = l; pos = u;
}
}
}
// ----- Suffix Automato Hacks -----------------------------------------
//
// Dependencies:
// -- Suffix Automaton
//
// bool find_substring(SuffixAutomaton sa, char[] a)
// void longest_common_substring(SuffixAutomaton sa, char[] a, out int pos, out int len)
// long number_of_different_substrings(char[] s)
// long total_length_of_different_substrings(char[] s)
// char[] least_cyclic_shift(char[] s)
// ---------------------------------------------------------------------
// bool test_find_substring(char[] s, char[] a)
// void test_longest_common_substring(char[] s, char[] a, out int pos, out int len)
// long test_number_of_different_substrings(char[] s)
// long test_total_length_of_different_substrings(char[] s)
// char[] test_least_cyclic_shift(char[] s)
// ---------------------------------------------------------------------
public static bool find_substring(SuffixAutomaton sa, char[] a)
{
SuffixAutomaton.Node v = sa.t0;
foreach (char c in a)
{
if (!v.ContainsKeyNext(c))
{
return(false);
}
v = v.GetNext(c);
}
return(true);
}
public static SuffixAutomaton Build(char[] str)
{
int n = str.Length;
SuffixAutomaton sa = new SuffixAutomaton(n);
sa.len = str.Length;
Node last = sa.t0;
foreach (char c in str)
{
last = sa.Extend(last, c);
}
return(sa);
}
public static long number_of_different_substrings(char[] s)
{
SuffixAutomaton sa = SuffixAutomaton.Build(s);
if (!sa.sortedTopologically)
{
sa.SortTopologically();
}
long[] D = new long[sa.gen];
for (int i = sa.gen - 1; i >= 0; i--)
{
D[i] = 1;
for (int j = 0; j < sa.nodes[i].np; j++)
{
D[i] += D[sa.nodes[i].next[j].id];
}
}
return(D[0] - 1);
}
public static char[] least_cyclic_shift(char[] s)
{
char[] ss = new char[s.Length * 2];
Buffer.BlockCopy(s, 0, ss, 0, sizeof(char) * s.Length);
Buffer.BlockCopy(s, 0, ss, sizeof(char) * s.Length, sizeof(char) * s.Length);
SuffixAutomaton sa = SuffixAutomaton.Build(ss);
if (!sa.lexsorted)
{
sa.LexSort();
}
SuffixAutomaton.Node v = sa.t0;
char[] a = new char[s.Length];
int ix = 0;
while (ix < s.Length)
{
v = v.next[0];
a[ix++] = v.key;
}
return(a);
}
