From bb22002cb96dd72364d1e206335b9e0a554dc197 Mon Sep 17 00:00:00 2001
From: alexchao26 <alexchaoo@gmail.com>
Date: Sat, 26 Dec 2020 02:18:04 -0500
Subject: [PATCH] 2015-day05: string validation

---
 2015/day05/main.go      | 87 +++++++++++++++++++++++++++++++++++++++++
 2015/day05/main_test.go | 41 +++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 2015/day05/main.go
 create mode 100644 2015/day05/main_test.go

diff --git a/2015/day05/main.go b/2015/day05/main.go
new file mode 100644
index 0000000..b8aa2d4
--- /dev/null
+++ b/2015/day05/main.go
@@ -0,0 +1,87 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+func main() {
+	var part int
+	flag.IntVar(&part, "part", 1, "part 1 or 2")
+	flag.Parse()
+	fmt.Println("Running part", part)
+
+	var ans int
+	if part == 1 {
+		ans = part1(util.ReadFile("./input.txt"))
+	} else {
+		ans = part2(util.ReadFile("./input.txt"))
+	}
+	fmt.Println("Output:", ans)
+}
+
+func part1(input string) int {
+	var nice int
+
+	disallowPattern := regexp.MustCompile("(ab|cd|pq|xy)")
+	for _, line := range strings.Split(input, "\n") {
+		var vowels int
+		for _, char := range line {
+			if strings.ContainsRune("aeiou", char) {
+				vowels++
+			}
+		}
+		var hasDouble bool
+		for i := 0; i < len(line)-1; i++ {
+			if line[i] == line[i+1] {
+				hasDouble = true
+				break
+			}
+		}
+		if vowels >= 3 && !disallowPattern.MatchString(line) && hasDouble {
+			nice++
+		}
+	}
+
+	return nice
+}
+
+func part2(input string) int {
+	var nice int
+
+	// put a double for loop check inside of a separate function b/c it makes
+	// returning out of both loops possible, and avoids using a label which
+	// makes me sad
+	passesRule1 := func(line string) bool {
+		for i := 0; i < len(line)-2; i++ {
+			toMatch := line[i : i+2]
+			for j := i + 2; j < len(line)-1; j++ {
+				if line[j:j+2] == toMatch {
+					return true
+				}
+			}
+		}
+		return false
+	}
+
+	for _, line := range strings.Split(input, "\n") {
+		rule1 := passesRule1(line)
+
+		var rule2 bool
+		for i := 0; i < len(line)-2; i++ {
+			if line[i] == line[i+2] {
+				rule2 = true
+				break
+			}
+		}
+		if rule1 && rule2 {
+			nice++
+		}
+	}
+
+	return nice
+}
diff --git a/2015/day05/main_test.go b/2015/day05/main_test.go
new file mode 100644
index 0000000..5da6cec
--- /dev/null
+++ b/2015/day05/main_test.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+func Test_part1(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"actual", util.ReadFile("input.txt"), 238},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := part1(tt.input); got != tt.want {
+				t.Errorf("part1() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_part2(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"actual", util.ReadFile("input.txt"), 69},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := part2(tt.input); got != tt.want {
+				t.Errorf("part2() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}