2022/4

Author: Jan Steinke

2022/4/main.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strconv"
+	"strings"
+)
+
+type (
+	section   int
+	shift     [2]int
+	shiftPair [2]shift
+)
+
+func main() {
+	content, err := ioutil.ReadFile("2022/4/input.txt")
+	if err != nil {
+		fmt.Print(err)
+	}
+	input := parse(content)
+	fmt.Println(countOverlap(input))
+}
+
+func parse(b []byte) (sps []shiftPair) {
+	lines := strings.Split(strings.TrimSpace(string(b)), "\n")
+	for _, l := range lines {
+		shifts := strings.Split(l, ",")
+		firstShift := shiftFromString(shifts[0])
+		secondShift := shiftFromString(shifts[1])
+		sps = append(sps, shiftPair{firstShift, secondShift})
+	}
+	return
+}
+
+func shiftFromString(s string) shift {
+	sections := strings.Split(strings.TrimSpace(s), "-")
+	start, err := strconv.Atoi(sections[0])
+	if err != nil {
+		panic(err)
+	}
+	end, err := strconv.Atoi(sections[1])
+	if err != nil {
+		panic(err)
+	}
+	return shift{start, end}
+}
+
+func countContaining(s []shiftPair) (c int) {
+	for _, sp := range s {
+		start1 := sp[0][0]
+		end1 := sp[0][1]
+		start2 := sp[1][0]
+		end2 := sp[1][1]
+		if start1 <= start2 && end1 >= end2 {
+			c++
+		} else if start1 >= start2 && end1 <= end2 {
+			c++
+		}
+	}
+	return
+}
+
+func countOverlap(s []shiftPair) (c int) {
+	for _, sp := range s {
+		start1 := sp[0][0]
+		end1 := sp[0][1]
+		start2 := sp[1][0]
+		end2 := sp[1][1]
+		if start1 <= end2 && end1 >= start2 {
+			c++
+		}
+	}
+	return
+}

2022/4/main_test.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParse(t *testing.T) {
+	input := []byte(`2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8`)
+
+	got := parse(input)
+
+	want := []shiftPair{
+		{{2, 4}, {6, 8}},
+		{{2, 3}, {4, 5}},
+		{{5, 7}, {7, 9}},
+		{{2, 8}, {3, 7}},
+		{{6, 6}, {4, 6}},
+		{{2, 6}, {4, 8}},
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got=%v, want=%v", got, want)
+	}
+}
+
+func TestCountContaining(t *testing.T) {
+	input := []shiftPair{
+		{{2, 4}, {6, 8}},
+		{{2, 3}, {4, 5}},
+		{{5, 7}, {7, 9}},
+		{{2, 8}, {3, 7}},
+		{{6, 6}, {4, 6}},
+		{{2, 6}, {4, 8}},
+	}
+
+	got := countContaining(input)
+
+	want := 2
+
+	if got != want {
+		t.Errorf("got=%v, want=%v", got, want)
+	}
+}
+
+func TestCountOverlap(t *testing.T) {
+	input := []shiftPair{
+		{{2, 4}, {6, 8}},
+		{{2, 3}, {4, 5}},
+		{{5, 7}, {7, 9}},
+		{{2, 8}, {3, 7}},
+		{{6, 6}, {4, 6}},
+		{{2, 6}, {4, 8}},
+	}
+
+	got := countOverlap(input)
+
+	want := 4
+
+	if got != want {
+		t.Errorf("got=%v, want=%v", got, want)
+	}
+}

README.md

@@ -1,3 +1,3 @@
 # adventofcode
 
-https://adventofcode.com/
+<https://adventofcode.com/>