fire.go

package main

import (
	"fmt"
)

// type number uint8

const (
	zero  int = 0x7E // 0b1111110   => 6
	one       = 0x30 // 0b0110000   => 2
	two       = 0x6d // 0b1101101   => 5
	three     = 0x79 // 0b1111001   => 5
	four      = 0x33 // 0b0110011   => 4
	five      = 0x5B // 0b1011011   => 5
	six       = 0x5f // 0b1011111   => 6
	seven     = 0x38 // 0b1110000   => 3
	eight     = 0x7F // 0b1111111   => 7
	nine      = 0x7B // 0b1111011   => 6
)

var arr = []int{zero, one, two, three, four, five, six, seven, eight, nine}

func sum16(number uint16) int {

	number = (number & 0x5555) + ((number >> 1) & 0x5555)
	number = (number & 0x3333) + ((number >> 2) & 0x3333)
	number = (number & 0x0F0F) + ((number >> 4) & 0x0F0F)
	number = (number & 0x00FF) + ((number >> 8) & 0x00FF)

	return int(number)
}

func sum32(number uint32) int {
	return int(sum16(uint16(number>>16)) + sum16(uint16(number)))
}

func num(n int) (r int) {

	if n/10 > 0 {
		r = arr[n/10] << 8
	}
	r |= arr[n%10]
	return
}

func recalc(m int) int {
	var (
		s int
	)

	fmt.Printf("calc: %d\n", m)
	for i := 0; i < m; i++ {
		for j := 0; j < m; j++ {
			var a, b, c, d int
			n := i + j
			if n > 0 && i !=j {

				a = num(i)
				b = num(j)
				c = num(i + j)
				d = sum32(uint32(a<<24 | b<<16 | c))
				if d == m-4 {
					s++
					fmt.Printf("%d + %d = %d\n", i, j, i+j)
				}

			}

		}
	}

	return s
}

func main() {
	s := recalc(18)
	fmt.Printf("total: %d\n", s)

}