static int levenWithSwapsSubstringIC(S haystack, S needle) {
  int m = strL(needle), n = strL(haystack);

  // base cases
  if (containsIgnoreCase(haystack, needle)) ret 0;

  int[] vx = new int[n+1], v0 = new int[n+1], v1 = new int[n+1];
  for i to m: { // iterate over needle
    v1[0] = i+1;
    for j to n: { // iterate over haystack
      int cost = neqic(needle.charAt(i), haystack.charAt(j)) ? 1 : 0;
      int d = min3(v1[j]+1,       // insertion
                       v0[j+1]+1,   // deletion
                       v0[j]+cost); // substitution
      if (i > 0 && j > 0 && equalsIgnoreCase(needle.charAt(i), haystack.charAt(j-1)) && equalsIgnoreCase(needle.charAt(i-1), haystack.charAt(j)))
        d = min(d, vx[j-1] + 1); // transposition
      v1[j+1] = d;
    }
    int[] temp = vx;
    vx = v0;
    v0 = v1;
    v1 = temp;
  }
  ret minOfIntArray(v0);
}