public string Analyse(string plainText, string cipherText) // O()
{
SortedDictionary <char, char> KeyTable = new SortedDictionary <char, char>();
Dictionary <char, bool> alphaList = new Dictionary <char, bool>();
int PTLength = plainText.Length;
int CTLength = cipherText.Length;
plainText = plainText.ToLower();
cipherText = cipherText.ToLower();
for (int i = 0; i < PTLength; i++) // O(N)
{
if (!KeyTable.ContainsKey(plainText[i]))
{
KeyTable.Add(plainText[i], cipherText[i]); alphaList.Add(cipherText[i], true);
}
}
if (KeyTable.Count != 26) //O(1)
{
Ceaser obj = new Ceaser();
string alphabet = obj.alphabet;
for (int i = 0; i < 26; i++)
{
if (!KeyTable.ContainsKey(alphabet[i]))
{
for (int j = 0; j < 26; j++)
{
if (!alphaList.ContainsKey(alphabet[j]))
{
KeyTable.Add(alphabet[i], alphabet[j]);
alphaList.Add(alphabet[j], true);
j = 26;
}
}
}
}
}
string key = "";
foreach (var item in KeyTable) // O(1)
{
key += item.Value;
}
return(key);
}
public Dictionary <char, char> KeyDictionary(string key, string Operation)// O(1)
{
Dictionary <char, char> dic = new Dictionary <char, char>();
Ceaser ceaser = new Ceaser();
for (int i = 0; i < 26; i++)
{
if (Operation == "encrypt")
{
dic.Add(ceaser.alphabet[i], key[i]);
}
else
{
dic.Add(key[i], ceaser.alphabet[i]);
}
}
return(dic);
}