From f7af519052bff018c49da96ea112d2afab50c9ac Mon Sep 17 00:00:00 2001
From: Carlos Sousa <me@carlossousa.tech>
Date: Thu, 19 Dec 2024 21:24:10 +0100
Subject: [PATCH] added 2024 day 03 solutio106921067n

---
 Advent of Code/2024/Day 03/simple_puzzle |  3 +
 Advent of Code/2024/Day 03/solution.go   | 94 +++++++++++++++++++-----
 2 files changed, 78 insertions(+), 19 deletions(-)
 create mode 100644 Advent of Code/2024/Day 03/simple_puzzle

diff --git a/Advent of Code/2024/Day 03/simple_puzzle b/Advent of Code/2024/Day 03/simple_puzzle
new file mode 100644
index 0000000..19d111b
--- /dev/null
+++ b/Advent of Code/2024/Day 03/simple_puzzle	
@@ -0,0 +1,3 @@
+xmul(2,4)&mul[3,7]!don't()
+^don't()_mul(5,5)+mul(32,64](mul(11,8)
+undo()?mul(8,5))
diff --git a/Advent of Code/2024/Day 03/solution.go b/Advent of Code/2024/Day 03/solution.go
index eb0fbf2..c5120e7 100644
--- a/Advent of Code/2024/Day 03/solution.go	
+++ b/Advent of Code/2024/Day 03/solution.go	
@@ -1,40 +1,96 @@
 package main
 
 import (
-	"bufio"
 	"fmt"
-    "strconv"
 	"log"
 	"os"
 	"regexp"
+	"strconv"
 )
 
+//var puzzle_input_file = "simple_puzzle"
 var puzzle_input_file = "puzzle_input"
-var regex_pattern_mul = `mul\((\d+),(\d+)\)`
-var regex_pattern_numbers = `(\d+)`
+var multiplier_expression = `mul\((\d+),(\d+)\)`
+var digits_expression = `(\d+)`
+var do_dont_expression = `do\(\)|don't\(\)`
+var string_do = `do()`
+var string_dont = `don't()`
 
-func main(){
-    file, err := os.Open(puzzle_input_file)
-    if err != nil {
-        log.Fatal(err)
+
+func find_dos_donts(input_string string) int {
+    do_dont_regex := regexp.MustCompile(do_dont_expression)
+    parts := do_dont_regex.FindAllStringIndex(input_string, -1)
+    current_result := 0
+    next_start_index := 0
+    is_multiplier_enabled := true
+    for _, part := range parts{
+        match_start := part[0]
+        match_end := part[1]
+        // first match, so check start or string -> now
+        if is_multiplier_enabled {
+            string_to_check := input_string[next_start_index:match_start]
+            mul_result := find_mul_in_string(string_to_check)
+            current_result += mul_result
+        }
+
+        next_start_index = match_end
+
+        // check which operation we got coming next
+        new_operation := input_string[match_start:match_end]
+        if new_operation == string_do{
+            if is_multiplier_enabled == false {
+                is_multiplier_enabled = true
+            }
+        }
+        if new_operation == string_dont{
+            if is_multiplier_enabled == true {
+                is_multiplier_enabled = false 
+            }
+        }
     }
-    defer file.Close()
 
+    // before exiting, handle the rest of the text
+    if is_multiplier_enabled{
+        string_to_check := input_string[next_start_index:]
+        mul_result := find_mul_in_string(string_to_check)
+        current_result += mul_result
+    }
+
+    return current_result
+}
+
+
+func find_mul_in_string(input_string string) int {
     final_answer := 0
-    file_scanner := bufio.NewScanner(file)
-    mul_regex := regexp.MustCompile(regex_pattern_mul) 
-
-    for file_scanner.Scan(){
-        current_line := file_scanner.Text()
-        all_matches := mul_regex.FindAllString(current_line, -1) 
-        for _, value := range all_matches {
-            numbers_regex := regexp.MustCompile(regex_pattern_numbers)
+    mul_regex := regexp.MustCompile(multiplier_expression)
+    //all_matches := mul_regex.FindAllString(input_string, -1)
+    all_matches := mul_regex.FindAllString(input_string, -1)
+    for _, value := range all_matches{
+            numbers_regex := regexp.MustCompile(digits_expression)
             numbers_matches := numbers_regex.FindAllString(value, -1)
             first_number, _ := strconv.Atoi(numbers_matches[0])
             second_number, _ := strconv.Atoi(numbers_matches[1])
             multiplication_result := first_number * second_number 
             final_answer += multiplication_result
-        }
     }
-    fmt.Println("Final Answer: ", final_answer)
+    return final_answer
+}
+
+func main(){
+    // if we read the file as a buffer like we did in the day 01 and 02
+    // we will get an error because we have multiple lines (6)
+    // therefore making the `final_answer_advanced` higher then it should
+    // since a new line will mean the mul(x,y) are valid
+    // imho that should be the right answer
+    input_file, err := os.ReadFile(puzzle_input_file)
+    if err != nil {
+        log.Fatal(err)
+    }
+    input_string := string(input_file)
+
+    final_answer := find_mul_in_string(input_string)
+    fmt.Println("Final Answer: ", final_answer)
+
+    final_answer_advanced := find_dos_donts(input_string) 
+    fmt.Println("Final Answer with do() / don't(): ", final_answer_advanced)
 }