Threads for artyom

1. 1. 5

      artyom 11 months ago | link | on: Faster Go code by being mindful of memory

      It’s possible to exploit the fact that inputs to hasDuplicates function are always of a known fixed size, and avoid extra allocation like this:

      const width = 14
      
      func hasDuplicates(bb []byte) bool {
      	if len(bb) != width {
      		panic(fmt.Errorf("want []byte of len %d, got %d", width, len(bb)))
      	}
      	var x uint64
      	for _, b := range bb {
      		x |= (1 << (b - 'a' - 1))
      	}
      	return bits.OnesCount64(x) == width
      }
      

      Same result, but we use a single uint64 as a bitmap.