[Tolnaftate2004]

Okay, well this thread has been dead for sufficiently long time. Here is what I came up with; it takes quadratic time.

PHP Code:

function onCreated() {
  temp.p = getpatterns("THISISATESTSTRING");
  for (temp.s: temp.p) {
    if (this.(@"h_"@temp.s) >= 2)
      echo(temp.s @ ": "@ this.(@"h_"@temp.s));
    this.(@"h_"@temp.s) = 0; /* clean-up */
  }
}

function getpatterns(s) {
  temp.l = s.length();
  for (temp.i=0; temp.i<temp.l-1; temp.i++) {
    temp.c = s.charat(temp.i);
    for (temp.j=temp.i+1;temp.j<temp.l;temp.j++) {
      temp.c @= s.charat(temp.j);
      this.(@"h_"@temp.c) ++;
      temp.pat.add(temp.c);
    }
  }
  return temp.pat;
} 


Perhaps there are still improvements to be made.