public void Compress()
{
string inputChars = input.ReadString();
var st = new TrieSymbolTable <int>();
// initialize symbol table
for (int i = 0; i < R; i++)
{
st.Put("" + (char)i, i);
}
int code = R + 1; // R is codeword for EOF
while (inputChars.Length > 0)
{
string s = st.LongestPrefixOf(inputChars);
output.Write(st[s], W);
int t = s.Length;
if (t < inputChars.Length && code < L)
{
// Add s to symbol table
st.Put(inputChars.Substring(0, t + 1), code++);
}
// Scan past s in input
inputChars = inputChars.Substring(t);
}
output.Write(R, W);
output.Close();
}
public void TrieSymbolTable()
{
var st = new TrieSymbolTable <int>();
st.Put("by", 4);
st.Put("sea", 2);
st.Put("sells", 1);
st.Put("she", 6);
st.Put("shells", 3);
st.Put("the", 5);
Assert.Equal(6, st.Size());
var keys = st.KeysWithPrefix("sh");
int i = 0;
var res = new string[] { "she", "shells" };
foreach (var key in keys)
{
Assert.Equal(key, res[i]);
i++;
}
Assert.Equal("she", st.LongestPrefixOf("she"));
Assert.Equal("she", st.LongestPrefixOf("shed"));
st.TryGet("shells", out var val1);
Assert.Equal(3, val1);
st.TryGet("shed", out var val2);
Assert.Equal(0, val2);
st.Delete("shells");
st.TryGet("shells", out var val3);
Assert.Equal(0, val3);
}
public void TernarySearchTrieSymbolTableTest()
{
var st = new TrieSymbolTable <int>();
st.Put("by", 4);
st.Put("sea", 2);
st.Put("sells", 1);
st.Put("she", 6);
st.Put("shells", 3);
st.Put("the", 5);
st.TryGet("by", out var val1);
Assert.Equal(4, val1);
st.TryGet("bye", out var val2);
Assert.Equal(0, val2);
}
