docs: public static boolean equal(long[] x, long[] y) {
      if(x == null || y == null) {
        return (x == null) && (y == null);
      }
      int p = Math.min(x.length, y.length) - 1;
      for(int i = x.length - 1; i > p; i--) {
        if(x[i] != 0L) {
          return false;
        }
      }
      for(int i = y.length - 1; i > p; i--) {
        if(y[i] != 0L) {
          return false;
        }
      }
      for(; p >= 0; p--) {
        if(x[p] != y[p]) {
          return false;
        }
      }
      return true;
    }