Some new things

2024/rust/inputs/day3test.txt

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

2024/rust/src/day3.rs

@@ -4,7 +4,6 @@ use std::process;
 use regex::Regex;
 
 pub fn run_day_3() -> Solution {
-    
     let file = fs::read_to_string("./inputs/day3.txt").expect("Unable to parse file");
     let re = Regex::new("mul\\((\\d{1,3}),(\\d{1,3})\\)").unwrap();
     let mut part1_sum = 0;
@@ -15,12 +14,58 @@ pub fn run_day_3() -> Solution {
         let total = num1 * num2;
         part1_sum += total;
     }
+    // get all matches of do and their index
+    // get all matches of dont and their index
+    let mut part2_sum = 0;
+    let dont_regex = Regex::new("don't\\(\\)").unwrap();
+    let do_regex = Regex::new("do\\(\\)").unwrap();
+    let mut donts: Vec<u64> = dont_regex.find(&file).map(|m| m.start() as u64).into_iter().collect();
+    let mut dos: Vec<u64> = do_regex.find(&file).map(|m| m.start() as u64).into_iter().collect();
+    for mul in re.captures_iter(&file) {
+        let start: usize = mul.get(1).unwrap().start();
+        // get the closest number, that is lower than the start value
+        let mut closest_dont = 0;
+        for i in (0..start).rev() {
+            // remove 1 becasue we want to search in reverse.
+            let mut index = i as u64;
+            if donts.contains(&index) {
+                closest_dont = index;
+                break;
+            }
+        }
+        let mut closest_do = 0;
+        for i in (0..start).rev() {
+            let mut index = i as u64;
+            if dos.contains(&index) {
+                closest_do = index;
+                break;
+            }
+        }
 
-    
+        println!("{:?} -> {:?}", closest_do, closest_dont);
+
+        if closest_do > closest_dont {
+            let num1: &u32 = &mul[1].parse().expect("Conversion failed");
+            let num2: &u32 = &mul[2].parse().expect("Conversion failed");
+            let total = num1 * num2;
+            part2_sum += total;  
+        }
+
+        if closest_do == 0 && closest_dont == 0 {
+            let num1: &u32 = &mul[1].parse().expect("Conversion failed");
+            let num2: &u32 = &mul[2].parse().expect("Conversion failed");
+            let total = num1 * num2;
+            part2_sum += total;  
+        }
+    }
+
+    // println!("{:?} -> {:?}", dos, donts);
+
+    // Final solutions here.
     let solution = Solution {
         day: 3,
         answer_1: part1_sum.to_string(),
-        answer_2: "Not sure".to_string(),
+        answer_2: part2_sum.to_string(),
     };
     
     solution