Source code plagiarism detection built for how programming is actually taught

int[] merge(int[] a, int[] b) {
  int[] out = new int[a.length + b.length];
  int i = 0, j = 0, k = 0;
  while (i < a.length && j < b.length) {
    if (a[i] <= b[j])
      out[k++] = a[i++];
    else
      out[k++] = b[j++];
  }
  while (i < a.length) out[k++] = a[i++];
  return out;
}

static int[] combine(int[] x, int[] y) {
  int[] res = new int[x.length + y.length];
  int p = 0, q = 0, r = 0;
  while (p < x.length && q < y.length) {
    if (x[p] <= y[q])
      res[r++] = x[p++];
    else
      res[r++] = y[q++];
  }
  // fill remaining
  while (q < y.length) res[r++] = y[q++];
}