code: func bitmapSetRangeIgnoreN(bitmap []uint64, i, j uint64) {
  	x := i >> 6
  	y := (j - 1) >> 6
  	var X uint64 = maxBitmap << (i % 64)
  	var Y uint64 = maxBitmap >> (63 - ((j - 1) % 64))
  
  	if x == y {
  		bitmap[x] |= (X & Y)
  	} else {
  		bitmap[x] |= X
  		for i := x + 1; i < y; i++ {
  			bitmap[i] = maxBitmap
  		}
  		bitmap[y] |= Y
  	}
  }
docs: // sets all bits in [i, j) without updating any corresponding n value.