Lecture Notes on 23 Jul 2013

// characters of s2 are in the same order in s1
public static boolean doesContain (String s1, String s2)
{
  int startIdx = 0;
  for (int i = 0; i < s2.length(); i++)
  {
    if (startIdx >= s2.length())
      return false;
    char ch = s2.charAt(i);
    int index = s1.indexOf(ch, startIdx);
    if (index == -1)
      return false;
    startIdx = index + 1;
  }
  return true;
}

// characters of s2 are not in the same order in s1
public static boolean doesContain (String s1, String s2)
{
  if (s2.length() > s1.length())
    return false;
  for (int i = 0; i < s2.length(); i++)
  {
    char ch = s2.charAt(i);
    int index = s1.indexOf(ch);
    if (index == -1) 
      return false;
    s1 = s1.replace(ch, '');
  }
  return true;
}