Another Casual Coder

Example :
Input: 
S = "cba"
T = "abcd"
Output: "cbad"
Explanation: 
"a", "b", "c" appear in S, so the order of "a", "b", "c" should be "c", "b", and "a". 
Since "d" does not appear in S, it can be at any position in T. "dcba", "cdba", "cbda" are also valid outputs.

• S has length at most 26, and no character is repeated in S.
• T has length at most 200.
• S and T consist of lowercase letters only.

public class Solution
{
 public string CustomSortString(string S, string T)
 {
 Hashtable order = new Hashtable();
 for (int i = 0; i < S.Length; i++)
 {
 order.Add(S[i], S.Length - i);
 }
 StringBuilder sb = new StringBuilder(T);
 int left = 0;
 int right = T.Length - 1;
 for (int i = 0; i < T.Length; i++)
 {
 if (order.ContainsKey(T[i]))
 {
 sb[left++] = T[i];
 }
 else
 {
 sb[right--] = T[i];
 }
 }
 bool sorted = false;
 while (!sorted)
 {
 sorted = true;
 for (int i = 0; i < T.Length - 1; i++)
 {
 if (order.ContainsKey(sb[i]) && order.ContainsKey(sb[i + 1]) && (int)order[sb[i]] < (int)order[sb[i + 1]])
 {
 char temp = sb[i];
 sb[i] = sb[i + 1];
 sb[i + 1] = temp;
 sorted = false;
 }
 }
 }
 return sb.ToString();
 }
}