-
Notifications
You must be signed in to change notification settings - Fork 0
/
main.go
83 lines (67 loc) · 1.51 KB
/
main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
// -*- compile-command: "go run main.go ../example1.txt ../input.txt"; -*-
package main
import (
"flag"
"fmt"
"log"
"strings"
"sync"
. "github.com/gmlewis/advent-of-code-2021/enum"
"github.com/gmlewis/advent-of-code-2021/must"
"github.com/gmlewis/advent-of-code-2021/stream"
)
var logf = log.Printf
var printf = fmt.Printf
func main() {
flag.Parse()
Each(flag.Args(), process)
}
func process(filename string) {
logf("Processing %v ...", filename)
lines := must.ReadFileLines(filename)
puz := &puzT{grid: map[keyT]bool{}}
puz = Reduce(lines, puz, parseLine)
surfaceArea := puz.surfaceArea()
printf("Solution: %v\n", surfaceArea)
}
type keyT [3]int
type puzT struct {
grid map[keyT]bool
}
func (p *puzT) cubeSurfaceArea(ch chan<- int, key keyT) {
var surfaceArea int
f := func(k keyT) {
if !p.grid[k] {
surfaceArea++
}
}
f(keyT{key[0] - 1, key[1], key[2]})
f(keyT{key[0] + 1, key[1], key[2]})
f(keyT{key[0], key[1] - 1, key[2]})
f(keyT{key[0], key[1] + 1, key[2]})
f(keyT{key[0], key[1], key[2] - 1})
f(keyT{key[0], key[1], key[2] + 1})
ch <- surfaceArea
}
func (p *puzT) surfaceArea() int {
ch := make(chan int, 1000)
var wg sync.WaitGroup
wg.Add(len(p.grid))
for k := range p.grid {
go func(k keyT) {
p.cubeSurfaceArea(ch, k)
wg.Done()
}(k)
}
go func() {
wg.Wait()
close(ch)
}()
return stream.Sum(ch)
}
func parseLine(line string, acc *puzT) *puzT {
parts := strings.Split(line, ",")
vs := Map(parts, must.Atoi)
acc.grid[keyT{vs[0], vs[1], vs[2]}] = true
return acc
}