/// <summary>
/// Recursively search the children of this <see cref="Node{T}"/> to find the key
/// <para>Returns 'null' if key does not have a value</para>
/// </summary>
internal Node <T> Search(string key)
{
if (key.Length == 1)
{
return(children[alphabet.ToIndex(key[0])]);
}
if (children[alphabet.ToIndex(key[0])] != null)
{
return(children[alphabet.ToIndex(key[0])].Search(key.Substring(1)));
}
return(null);
}
public int Search(string s)
{
int N = s.Length;
int M = pat.Length;
int skip;
for (int i = 0; i <= N - M; i += skip)
{
skip = 0;
for (int j = M - 1; j >= 0; j--)
{
if (pat[j] != s[i + j])
{
skip = j - right[alphabet.ToIndex(s[i + j])];
if (skip < 1)
{
skip = 1;
}
break;
}
}
if (skip == 0)
{
return(i); // found.
}
}
return(-1); // not found
}
public SubstringSearchKMP(string pat, IAlphabet alphabet)
{
this.pat = pat;
this.alphabet = alphabet;
int M = pat.Length;
int R = alphabet.R;
dfa = new int[R, M];
dfa[alphabet.ToIndex(pat[0]), 0] = 1;
for (int X = 0, j = 1; j < M; j++)
{
for (int r = 0; r < R; r++)
{
dfa[r, j] = dfa[r, X];
}
dfa[alphabet.ToIndex(pat[j]), j] = j + 1;
X = dfa[alphabet.ToIndex(pat[j]), X];
}
}
public int Search(string s)
{
int i;
int j;
int N = s.Length;
int M = pat.Length;
for (i = 0, j = 0; i < N && j < M; i++)
{
j = dfa[alphabet.ToIndex(s[i]), j];
}
return(j == M ? i - M : -1);
}
public void Sort(string[] a, int w)
{
string[] aux = new string[a.Length];
for (int d = w - 1; d >= 0; d--)
{
// Sort by key-indexed counting on dth char
// Compute frequency count
int[] count = new int[alphabet.R + 1];
for (int i = 0; i < a.Length; i++)
{
int charIndex = alphabet.ToIndex(a[i][d]);
count[charIndex + 1]++;
}
// Transform counts to indices
for (int r = 0; r < alphabet.R; r++)
{
count[r + 1] += count[r];
}
// Distribute
for (int i = 0; i < a.Length; i++)
{
int charIndex = alphabet.ToIndex(a[i][d]);
aux[count[charIndex]++] = a[i];
}
// Copy back
for (int i = 0; i < a.Length; i++)
{
a[i] = aux[i];
}
}
}
public SubstringSearchBoyerMoore(string pat, IAlphabet alphabet)
{
this.pat = pat;
this.alphabet = alphabet;
int M = pat.Length;
int R = alphabet.R;
right = new int[R];
for (int r = 0; r < R; r++)
{
right[r] = -1;
}
for (int j = 0; j < M; j++)
{
right[alphabet.ToIndex(pat[j])] = j;
}
}