[ADD] main: Added day 3 solution

03/main.go

@@ -0,0 +1,249 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const FILE_PATH = "./input.txt"
+
+//const FILE_PATH = "./sample.txt"
+
+func LoadInput(filename string) ([]string, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var lines []string
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return lines, nil
+}
+
+type structuredInput = string
+
+func TransformInput(lines []string) structuredInput {
+	return strings.Join(lines, "")
+}
+
+const PRE_FIX = "mul("
+
+func IsNummeric(input byte) bool {
+	return input >= '0' && input <= '9'
+}
+
+func ExtractNumber(input string, start_index int) (int, int, bool) {
+	var end_index = start_index
+	if !IsNummeric(input[start_index]) {
+		return -1, -1, false
+	}
+	for i := start_index; i < len(input); i++ {
+		if !IsNummeric(input[i]) {
+			break
+		}
+		end_index = i
+	}
+	result, error := strconv.Atoi(input[start_index : end_index+1])
+	if error != nil {
+		return -1, -1, false
+	}
+	return result, end_index - start_index + 1, true
+}
+
+func CalculateLinePart1(input string) int {
+	var error = -1
+	var success = false
+	var num1 = 0
+	var num2 = 0
+	var num_length = 0
+	var index = 0
+	var result = 0
+	for i := 0; i < len(input); i++ {
+		error = -1
+		for j := 0; j < len(PRE_FIX) && i+j < len(input); j++ {
+			if PRE_FIX[j] != input[i+j] {
+				error = i + j
+				break
+			}
+		}
+		index = i + len(PRE_FIX)
+
+		if error != -1 {
+			i = error
+			continue
+		}
+
+		num1 = 0
+		num2 = 0
+
+		num1, num_length, success = ExtractNumber(input, index)
+
+		if !success {
+			continue
+		}
+
+		index += num_length
+
+		if input[index] != ',' {
+			continue
+		}
+
+		index++
+
+		num2, num_length, success = ExtractNumber(input, index)
+
+		if !success {
+			continue
+		}
+		index += num_length
+
+		if input[index] != ')' {
+			continue
+		}
+		result += num1 * num2
+		i = index
+	}
+
+	return result
+}
+
+func Part1(input structuredInput) int {
+	return CalculateLinePart1(input)
+}
+
+type Method struct {
+	method string
+	num1   int
+	num2   int
+}
+
+var METHODS = map[string]func(paramters string) (bool, Method){
+	"mul": func(paramters string) (bool, Method) {
+		var num_length1 = 0
+		var num_length2 = 0
+		var success = false
+		var num1 = 0
+		var num2 = 0
+
+		num1, num_length1, success = ExtractNumber(paramters, 0)
+
+		if !success {
+			return false, Method{}
+		}
+
+		if len(paramters) <= num_length1 || paramters[num_length1] != ',' {
+			return false, Method{}
+		}
+
+		num2, num_length2, success = ExtractNumber(paramters, num_length1+1)
+
+		if !success {
+			return false, Method{}
+		}
+
+		if len(paramters) > num_length1+num_length2+1 {
+			return false, Method{}
+		}
+
+		return true, Method{"mul", num1, num2}
+	},
+	"do": func(paramters string) (bool, Method) {
+		return len(paramters) == 0, Method{"do", -1, -1}
+	},
+	"don't": func(paramters string) (bool, Method) {
+		return len(paramters) == 0, Method{"don't", -1, -1}
+	},
+}
+
+func IsMethod(line string, method_name string, start_index int) bool {
+	if start_index+len(method_name) >= len(line) {
+		return false
+	}
+	for i := 0; i < len(method_name); i++ {
+		if line[start_index+i] != method_name[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func CalculateLinePart2(line string) int {
+	var result = 0
+	var para_start = 0
+	var para_end = 0
+
+	var success = false
+	var code = make([]Method, 0)
+	var temp Method
+	for i := 0; i < len(line); i++ {
+		for method := range METHODS {
+			if !IsMethod(line, method, i) {
+				continue
+			}
+			para_start = i + len(method)
+			if line[para_start] != '(' {
+				continue
+			}
+			para_end = para_start
+			for para_end < len(line) && line[para_end] != ')' {
+				para_end++
+			}
+
+			if line[para_end] != ')' {
+				continue
+			}
+			success, temp = METHODS[method](line[para_start+1 : para_end])
+			if success {
+				code = append(code, temp)
+				break
+			}
+		}
+	}
+
+	var enabled = true
+	for _, method := range code {
+		switch method.method {
+		case "do":
+			enabled = true
+		case "don't":
+			enabled = false
+		case "mul":
+			if enabled {
+				result += method.num1 * method.num2
+			}
+		}
+
+	}
+
+	return result
+}
+
+func Part2(input structuredInput) int {
+	return CalculateLinePart2(input)
+}
+
+func main() {
+	input, err := LoadInput(FILE_PATH)
+	if err != nil {
+		fmt.Println("Error loading input:", err)
+		return
+	}
+
+	structuredInput := TransformInput(input)
+	fmt.Println("Structured Input:", structuredInput)
+
+	fmt.Println("Solution Part 1: ", Part1(structuredInput))
+	fmt.Println("Solution Part 2: ", Part2(structuredInput))
+}

03/sample.txt

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))