public void Should_Return_TIST()
{
String str = "this is a test string";
String pat = "tist";
String result = item.FindSubString(str, pat);
Assert.True(result == "t stri");
}
// Function to find smallest window containing
// all characters of 'pat'
public String FindSubString(String str)
{
HashSet <char> found = new HashSet <char>();
StringBuilder sb = new StringBuilder();
foreach (var c in str)
{
if (!found.Contains(c))
{
found.Add(c);
sb.Append(c);
}
}
SmallestWindowContainingAllCharsOfString smallest = new SmallestWindowContainingAllCharsOfString();
String result = smallest.FindSubString(str, sb.ToString());
return(result);
}