-
Notifications
You must be signed in to change notification settings - Fork 0
/
day02.go
82 lines (73 loc) · 1.74 KB
/
day02.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
// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package day02 solves AoC 2017 day 2.
package day02
import (
"fmt"
"github.com/fis/aoc/glue"
"github.com/fis/aoc/util"
)
func init() {
glue.RegisterSolver(2017, 2, glue.LineSolver(solve))
}
func solve(lines []string) ([]string, error) {
sheet := make([][]int, len(lines))
for i, line := range lines {
sheet[i] = util.Ints(line)
}
p1 := checksumSheet(sheet)
p2, err := divisibleSheet(sheet)
if err != nil {
return nil, err
}
return glue.Ints(p1, p2), nil
}
func checksumSheet(rows [][]int) (sum int) {
for _, row := range rows {
sum += checksumRow(row)
}
return sum
}
func checksumRow(row []int) int {
min, max := row[0], row[0]
for _, n := range row[1:] {
if n < min {
min = n
}
if n > max {
max = n
}
}
return max - min
}
func divisibleSheet(rows [][]int) (sum int, err error) {
for _, row := range rows {
d, err := divisibleRow(row)
if err != nil {
return 0, err
}
sum += d
}
return sum, nil
}
func divisibleRow(row []int) (int, error) {
for _, i := range row {
for _, j := range row {
if i > j && i%j == 0 {
return i / j, nil
}
}
}
return 0, fmt.Errorf("invalid input: %v: no evenly divisible pair", row)
}