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package main
import (
"fmt"
"math"
"strings"
)
type Position struct {
x, y int
}
type Movement struct {
from Position
to Position
}
type Keypad struct {
keys map[byte]Position
forbidden Position
}
var numpad = Keypad{
keys: map[byte]Position{
'7': {0, 0},
'8': {1, 0},
'9': {2, 0},
'4': {0, 1},
'5': {1, 1},
'6': {2, 1},
'1': {0, 2},
'2': {1, 2},
'3': {2, 2},
'0': {1, 3},
'A': {2, 3},
},
forbidden: Position{0, 3},
}
var dirpad = Keypad{
keys: map[byte]Position{
'^': {1, 0},
'A': {2, 0},
'<': {0, 1},
'v': {1, 1},
'>': {2, 1},
},
forbidden: Position{0, 0},
}
type DpKey struct {
code string
depth int
}
func main() {
fmt.Println(part1("029A"), 68)
fmt.Println(part1("980A"), 60)
fmt.Println(part1("179A"), 68)
fmt.Println(part1("456A"), 64)
fmt.Println(part1("379A"), 64)
fmt.Println("")
fmt.Println(137870)
fmt.Println(part1("805A")*805 + part1("170A")*170 + part1("129A")*129 + part1("283A")*283 + part1("540A")*540)
fmt.Println("")
fmt.Println(part2("029A"))
fmt.Println(part2("980A"))
fmt.Println(part2("179A"))
fmt.Println(part2("456A"))
fmt.Println(part2("379A"))
fmt.Println("")
fmt.Println(170279148659464)
fmt.Println(part2("805A")*805 + part2("170A")*170 + part2("129A")*129 + part2("283A")*283 + part2("540A")*540)
}
func part1(code string) int {
memo := make(map[DpKey]int)
return typeCode(memo, code, []Keypad{numpad, dirpad, dirpad}, 0)
}
func part2(code string) int {
memo := make(map[DpKey]int)
return typeCode(memo, code, []Keypad{
numpad,
dirpad, dirpad, dirpad, dirpad, dirpad,
dirpad, dirpad, dirpad, dirpad, dirpad,
dirpad, dirpad, dirpad, dirpad, dirpad,
dirpad, dirpad, dirpad, dirpad, dirpad,
dirpad, dirpad, dirpad, dirpad, dirpad,
}, 0)
}
func combine(prefix []string, suffix []string) (res []string) {
for _, p := range prefix {
for _, s := range suffix {
res = append(res, p+s)
}
}
return
}
func typeCode(memo map[DpKey]int, code string, keypads []Keypad, depth int) int {
subCode := strings.Split(code, "A")
subCode = subCode[:len(subCode)-1]
cost := 0
for _, subCode := range subCode {
cost += typeSubCode(memo, subCode+"A", keypads, depth)
}
return cost
}
func typeSubCode(memo map[DpKey]int, code string, keypads []Keypad, depth int) int {
if cost, isIn := memo[DpKey{code, depth}]; isIn {
return cost
}
codeSeqs := []string{}
{
pos := keypads[depth].keys['A']
seqs := []string{""}
for i := range code {
nextPos := keypads[depth].keys[code[i]]
childSeqs := buildSeqs(keypads[depth], pos, nextPos)
seqs = combine(seqs, childSeqs)
pos = nextPos
}
codeSeqs = append(codeSeqs, seqs...)
}
minCost := math.MaxInt
if depth < len(keypads)-1 {
for _, seq := range codeSeqs {
minCost = min(typeCode(memo, seq, keypads, depth+1), minCost)
}
} else {
for _, seq := range codeSeqs {
minCost = min(len(seq), minCost)
}
}
memo[DpKey{code, depth}] = minCost
return minCost
}
func shortestSeq(seqs []string) int {
minLength := math.MaxInt
for _, s := range seqs {
minLength = min(minLength, len(s))
}
return minLength
}
func buildSeqs(kp Keypad, from, to Position) (seqs []string) {
type Step struct {
p Position
seq string
}
steps := []Step{{from, ""}}
for len(steps) > 0 {
nextSteps := []Step{}
for _, s := range steps {
if s.p == to {
seqs = append(seqs, s.seq+"A")
continue
}
if s.p.x < to.x && !(s.p.x+1 == kp.forbidden.x && s.p.y == kp.forbidden.y) {
nextSteps = append(nextSteps, Step{Position{s.p.x + 1, s.p.y}, s.seq + ">"})
} else if s.p.x > to.x && !(s.p.x-1 == kp.forbidden.x && s.p.y == kp.forbidden.y) {
nextSteps = append(nextSteps, Step{Position{s.p.x - 1, s.p.y}, s.seq + "<"})
}
if s.p.y < to.y && !(s.p.y+1 == kp.forbidden.y && s.p.x == kp.forbidden.x) {
nextSteps = append(nextSteps, Step{Position{s.p.x, s.p.y + 1}, s.seq + "v"})
} else if s.p.y > to.y && !(s.p.y-1 == kp.forbidden.y && s.p.x == kp.forbidden.x) {
nextSteps = append(nextSteps, Step{Position{s.p.x, s.p.y - 1}, s.seq + "^"})
}
}
steps = nextSteps
}
if len(seqs) == 0 {
seqs = []string{"A"}
}
return
}
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