Part 2 bruteforced, wasnt that hard and quick enough, day 18

advent_of_code/2024/18/src/main.rs

@@ -11,13 +11,13 @@ fn parse(input: &str) -> Vec<(i64, i64)> {
         .collect()
 }
 
-fn solve_1(input: &str, steps: usize, range: i64) -> i64 {
+fn solve_1(input: &str, steps: usize, range: i64) -> Option<i64> {
     let memory = parse(input);
     let memory: HashSet<_> = memory[..steps].into_iter().collect();
 
     let mut visited: HashSet<(i64, i64)> = HashSet::new();
     let mut path_length = 0;
-    let mut stack = [(0, 0)].into_iter().collect();
+    let mut stack: HashSet<_> = [(0, 0)].into_iter().collect();
 
     let dirs = [(1, 0), (-1, 0), (0, 1), (0, -1)];
 
@@ -25,9 +25,13 @@ fn solve_1(input: &str, steps: usize, range: i64) -> i64 {
         path_length += 1;
         let mut new_stack = HashSet::new();
 
+        if stack.is_empty() {
+            return None;
+        }
+
         for pos in stack {
             if pos == (range, range) {
-                return path_length - 1;
+                return Some(path_length - 1);
             }
 
             visited.insert(pos);
@@ -46,7 +50,17 @@ fn solve_1(input: &str, steps: usize, range: i64) -> i64 {
     }
 }
 
-fn solve_2(input: &str) {}
+fn solve_2(input: &str, range: i64) -> (i64, i64) {
+    let memory = parse(input);
+
+    for i in 0..memory.len() {
+        if solve_1(input, i, range).is_none() {
+            return memory[i - 1];
+        }
+    }
+
+    return (0, 0);
+}
 
 fn main() {
     println!("Hello, this is Patrick!");
@@ -54,10 +68,16 @@ fn main() {
     let input = include_str!("../input.txt");
 
     let result_1 = solve_1(input, 1024, 70);
-    println!("{}", result_1);
+    println!(
+        "The number of steps of the shortest route from beginning to end is {}",
+        result_1.unwrap()
+    );
 
-    let result_2 = solve_2(input);
-    //println!("{}", result_2);
+    let result_2 = solve_2(input, 70);
+    println!(
+        "The first byte that prevents a path being laid is {},{}",
+        result_2.1, result_2.0
+    );
 }
 
 #[cfg(test)]
@@ -67,12 +87,12 @@ mod tests {
     #[test]
     fn test_1() {
         let test_input = include_str!("../test.txt");
-        assert_eq!(solve_1(test_input, 12, 6), 22);
+        assert_eq!(solve_1(test_input, 12, 6).unwrap(), 22);
     }
 
     #[test]
     fn test_2() {
-        //let test_input = include_str!("../test.txt");
-        //assert_eq!(solve_2(test_input), _);
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_2(test_input, 6), (1, 6));
     }
 }