commit 07d24c2e8a5d1b4830bab7bc2b6e2889dc27da80
Author: onyx-and-iris <code@onyxandiris.online>
Date:   Sat Dec 2 15:07:04 2023 +0000

    day-1

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5bd2407
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,24 @@
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+# input files
+input.txt
\ No newline at end of file
diff --git a/day-1/go.mod b/day-1/go.mod
new file mode 100644
index 0000000..9eb1bf5
--- /dev/null
+++ b/day-1/go.mod
@@ -0,0 +1,11 @@
+module github.com/onyx-and-iris/aoc2023/day-1
+
+go 1.20
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
diff --git a/day-1/go.sum b/day-1/go.sum
new file mode 100644
index 0000000..fa4b6e6
--- /dev/null
+++ b/day-1/go.sum
@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/day-1/one.go b/day-1/one.go
new file mode 100644
index 0000000..a32cc1d
--- /dev/null
+++ b/day-1/one.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+// one takes a string array and for each line:
+// Combine the first digit and the last digit (in that order) to form a single two-digit number.
+// Returns the sum of all calibrated values.
+func one(lines []string) (int, error) {
+	re := regexp.MustCompile(`\d`)
+
+	sum := 0
+	for _, line := range lines {
+		m := re.FindAllString(line, -1)
+		if len(m) > 0 {
+			num, err := strconv.Atoi(fmt.Sprintf("%s%s", m[0], m[len(m)-1]))
+			if err != nil {
+				return 0, err
+			}
+			sum += num
+		}
+	}
+	return sum, nil
+}
diff --git a/day-1/one_test.go b/day-1/one_test.go
new file mode 100644
index 0000000..b33a0e7
--- /dev/null
+++ b/day-1/one_test.go
@@ -0,0 +1,22 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestOne(t *testing.T) {
+	//t.Skip("skipping test")
+	input := []string{
+		"1abc2",
+		"pqr3stu8vwx",
+		"a1b2c3d4e5f",
+		"treb7uchet",
+	}
+	retval, _ := one(input)
+
+	t.Run("Return the sum of all calibrated numbers, solution one", func(t *testing.T) {
+		assert.Equal(t, 142, retval)
+	})
+}
diff --git a/day-1/run.sh b/day-1/run.sh
new file mode 100755
index 0000000..3f6776a
--- /dev/null
+++ b/day-1/run.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+INPUT="input.txt"
+
+cat $INPUT | go run .
\ No newline at end of file
diff --git a/day-1/solution.go b/day-1/solution.go
new file mode 100644
index 0000000..3ea39e6
--- /dev/null
+++ b/day-1/solution.go
@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+	"log"
+)
+
+func main() {
+	lines := readlines()
+
+	ans, err := one(lines)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("solution one: %d\n", ans)
+
+	ans, err = two(lines)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("solution two: %d\n", ans)
+}
diff --git a/day-1/two.go b/day-1/two.go
new file mode 100644
index 0000000..048e4ba
--- /dev/null
+++ b/day-1/two.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+var replaceMap = map[string]string{
+	"one":   "1",
+	"two":   "2",
+	"three": "3",
+	"four":  "4",
+	"five":  "5",
+	"six":   "6",
+	"seven": "7",
+	"eight": "8",
+	"nine":  "9",
+}
+
+var r = regexp.MustCompile(`\d|one|two|three|four|five|six|seven|eight|nine`)
+var rr = regexp.MustCompile(`\d|eno|owt|eerht|ruof|evif|xis|neves|thgie|enin`)
+
+// forward parses a single line from start to last
+// Match all substrings matching `\d|one|two|three|four|five|six|seven|eight|nine`
+// Returns the first match
+func forward(s string) string {
+	m_all := r.FindAllString(s, -1)
+	match := m_all[0]
+	match, ok := replaceMap[match]
+	if !ok {
+		match = m_all[0]
+	}
+
+	return match
+}
+
+// backward parses a single line in reverse order
+// Match all substrings matching `\d|eno|owt|eerht|ruof|evif|xis|neves|thgie|enin`
+// Returns the first match
+func backward(s string) string {
+	m_all := rr.FindAllString(s, -1)
+	match := m_all[0]
+	match, ok := replaceMap[reverse(match)]
+	if !ok {
+		match = m_all[0]
+	}
+
+	return match
+}
+
+// two takes a string array and for each line:
+// Search by regex all substrings matching numeric (and word representations of numeric) values.
+// It then combines the first digit and the last digit (in that order) to form a single two-digit number.
+// Returns the sum of all calibrated values.
+func two(lines []string) (int, error) {
+	sum := 0
+	for _, line := range lines {
+		m1 := forward(line)
+		m2 := backward(reverse(line))
+		n, err := strconv.Atoi(fmt.Sprintf("%s%s", m1, m2))
+		if err != nil {
+			return 0, err
+		}
+		sum += n
+	}
+	return sum, nil
+}
diff --git a/day-1/two_test.go b/day-1/two_test.go
new file mode 100644
index 0000000..11acae3
--- /dev/null
+++ b/day-1/two_test.go
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTwo(t *testing.T) {
+	//t.Skip("skipping test")
+	input := []string{
+		"two1nine",
+		"eightwothree",
+		"abcone2threexyz",
+		"xtwone3four",
+		"4nineeightseven2",
+		"zoneight234",
+		"7pqrstsixteen",
+	}
+	retval, _ := two(input)
+
+	t.Run("Return the sum of all calibrated numbers, solution two", func(t *testing.T) {
+		assert.Equal(t, 281, retval)
+	})
+}
diff --git a/day-1/util.go b/day-1/util.go
new file mode 100644
index 0000000..d052dc3
--- /dev/null
+++ b/day-1/util.go
@@ -0,0 +1,32 @@
+package main
+
+import (
+	"bufio"
+	"log"
+	"os"
+)
+
+// readlines reads lines from stdin.
+// Then it returns them as an array of strings
+func readlines() []string {
+	lines := []string{}
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return lines
+}
+
+// reverse accepts a string and returns its reverse
+func reverse(s string) (result string) {
+	for _, v := range s {
+		result = string(v) + result
+	}
+	return
+}
diff --git a/day-1/util_test.go b/day-1/util_test.go
new file mode 100644
index 0000000..2929004
--- /dev/null
+++ b/day-1/util_test.go
@@ -0,0 +1,16 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReverse(t *testing.T) {
+	//t.Skip("skipping test")
+	input := "eightwone3"
+	expected := "3enowthgie"
+	t.Run("Should reverse the string", func(t *testing.T) {
+		assert.Equal(t, expected, reverse(input))
+	})
+}