public int Rank(char c, int stop, out WaveletTreeNodeAsc next, out bool done)
{
if (!groupMembership.ContainsKey(c)) {
next = null;
done = true;
return 0;
}
else {
bool bit = groupMembership[c];
int rank = bitString.Rank(bit, stop);
next = bit ? right : left;
done = next == null;
return rank;
}
}
public WaveletTreeNodeAsc(string text, NodeList leaves)
{
List<char> distinctCharList = text.Distinct<char>().ToList<char>();
distinctCharList.Sort();
string distinctChars = new string(distinctCharList.ToArray<char>());
// Leaf Node
if (distinctChars.Length == 1) {
BitArray bitArray = new BitArray(text.Length);
bitString = new BitString(bitArray);
groupMembership = new Dictionary<char, bool>();
groupMembership[text[0]] = false;
left = null;
right = null;
leaves.Add(text[0], this);
}
// Inner Node
else {
string charsGroup1 = distinctChars.Substring(0, distinctChars.Length / 2);
string charsGroup2 = distinctChars.Substring(distinctChars.Length / 2);
groupMembership = new Dictionary<char, bool>(charsGroup1.Length + charsGroup2.Length);
foreach (char c in charsGroup1)
groupMembership[c] = false;
foreach (char c in charsGroup2)
groupMembership[c] = true;
string group1 = "";
string group2 = "";
BitArray bitArray = new BitArray(text.Length);
for (int i = 0; i < text.Length; i++) {
if (charsGroup1.Contains(text[i])) {
group1 += text[i];
bitArray[i] = false;
}
else {
group2 += text[i];
bitArray[i] = true;
}
}
bitString = new BitString(bitArray);
left = new WaveletTreeNodeAsc(group1, leaves);
right = new WaveletTreeNodeAsc(group2, leaves);
left.parent = right.parent = this;
}
}
public WaveletTreeAsc(string text)
{
leaves = new NodeList();
this.root = new WaveletTreeNodeAsc(text, leaves);
}
public int Select(char c, int count, out WaveletTreeNodeAsc next, out bool done)
{
next = null;
done = true;
if (groupMembership == null || !groupMembership.ContainsKey(c))
return -1;
bool bit = groupMembership[c];
int select = bitString.Select(bit, count);
next = parent;
done = next == null;
return select;
}
