From b3827cf53adbc2b542d66d865874be3b9aee5b80 Mon Sep 17 00:00:00 2001
From: Luke Else <mail@luke-else.co.uk>
Date: Fri, 3 Dec 2021 21:04:10 +0000
Subject: [PATCH] day 3b complete

---
 day3/3b/go.mod    |  3 ++
 day3/3b/main.go   | 96 +++++++++++++++++++++++++++++++++++++++++++++++
 day3/3b/testInput | 12 ++++++
 3 files changed, 111 insertions(+)
 create mode 100644 day3/3b/go.mod
 create mode 100644 day3/3b/main.go
 create mode 100644 day3/3b/testInput

diff --git a/day3/3b/go.mod b/day3/3b/go.mod
new file mode 100644
index 0000000..e938e2e
--- /dev/null
+++ b/day3/3b/go.mod
@@ -0,0 +1,3 @@
+module PWD
+
+go 1.17
diff --git a/day3/3b/main.go b/day3/3b/main.go
new file mode 100644
index 0000000..18d0aed
--- /dev/null
+++ b/day3/3b/main.go
@@ -0,0 +1,96 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math"
+	"os"
+)
+
+func main() {
+	content := returnContent("../input")
+
+	//content := returnContent("testInput")
+
+	oxygen, carbon := findOxygenAndCarbon(content, 0)
+
+	fmt.Println(oxygen, carbon)
+
+	fmt.Println(binaryToInteger(oxygen) * binaryToInteger(carbon))
+}
+
+func findOxygenAndCarbon(content *[]string, i int) (oxygen string, carbon string) {
+	//recursion
+
+	oxygen = (*findValues(content, 0, true))[0]
+
+	carbon = (*findValues(content, 0, false))[0]
+
+	return
+}
+
+//recursively find the values that fit the criteria
+func findValues(content *[]string, i int, inclusive bool) (values *[]string) {
+
+	if len(*content) <= 1 {
+		return content
+	}
+
+	count := 0
+	var bit byte = '0'
+	for j := 0; j < len(*content); j++ {
+		if ((*content)[j])[i] == '1' {
+			count++
+		}
+	}
+
+	if inclusive {
+		if float64(count) >= float64(len(*content))/2 {
+			bit = '1'
+		}
+	} else {
+		if float64(count) < float64(len(*content))/2 {
+			bit = '1'
+		}
+	}
+
+	var newContent []string
+	for j := 0; j < len(*content); j++ {
+		if ((*content)[j])[i] == bit {
+			newContent = append(newContent, (*content)[j])
+		}
+	}
+	i++
+	return findValues(&newContent, i, inclusive)
+}
+
+func binaryToInteger(input string) (value int) {
+	n := 0
+	for i := len(input) - 1; i >= 0; i-- {
+		if input[i] == '1' {
+			value += (int(math.Pow(float64(2), float64(n))))
+		}
+		n++
+	}
+	return
+}
+
+func returnContent(path string) *[]string {
+	//read file and return it as an array of integers
+
+	file, err := os.Open(path)
+	var content []string
+
+	if err != nil {
+		fmt.Println("Unlucky, the file didn't open")
+		return &content
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		content = append(content, scanner.Text())
+	}
+
+	return &content
+}
diff --git a/day3/3b/testInput b/day3/3b/testInput
new file mode 100644
index 0000000..665fd57
--- /dev/null
+++ b/day3/3b/testInput
@@ -0,0 +1,12 @@
+00100
+11110
+10110
+10111
+10101
+01111
+00111
+11100
+10000
+11001
+00010
+01010
\ No newline at end of file