Dag 7 aoc klaar, basically een soort 3-sat

advent_of_code/2024/7/src/main.rs

@@ -1,69 +1,101 @@
 use nom::{
     bytes::complete::tag,
-    character::complete::{i32, multispace1},
+    character::complete::{i64, multispace1},
     multi::separated_list1,
     sequence::separated_pair,
     IResult,
 };
 
-fn parse(input: &str) -> IResult<&str, Vec<(i32, Vec<i32>)>> {
+fn parse(input: &str) -> IResult<&str, Vec<(i64, Vec<i64>)>> {
     let (input, result) = separated_list1(
         multispace1,
-        separated_pair(i32, tag(": "), separated_list1(tag(" "), i32)),
+        separated_pair(i64, tag(": "), separated_list1(tag(" "), i64)),
     )(input)?;
 
     Ok((input, result))
 }
 
-fn check(original_target: i32, line: &[i32]) -> Option<i32> {
-    //dbg!(original_target, &line);
-    if line.iter().fold(1, |p, n| p * n) > original_target {
+fn check(original_target: i64, line: &[i64]) -> Option<i64> {
+    let mut target = original_target;
+
+    for (i, number) in line.iter().enumerate().rev() {
+        if i == 0 && target == *number {
+            return Some(original_target);
+        }
+
+        if target % number == 0 {
+            if check(target - number, &line[..i]).is_some() {
+                return Some(original_target);
+            }
+
+            target /= number;
+        } else {
+            target -= number;
+        }
+    }
+
+    None
+}
+
+fn solve_1(input: &str) -> i64 {
+    let (_, lines) = parse(input).unwrap();
+
+    lines.into_iter().fold(0, |result, line| {
+        check(line.0, &line.1[..]).unwrap_or_default() + result
+    })
+}
+
+fn check_2(original_target: i64, numbers: &[i64]) -> Option<i64> {
+    if let Some((i, number)) = numbers.iter().enumerate().rev().next() {
+        if i == 0 && original_target == *number {
+            return Some(original_target);
+        }
+
+        if original_target % number == 0 {
+            if check_2(original_target / number, &numbers[..i]).is_some() {
+                return Some(original_target);
+            }
+        }
+        if original_target - number >= 0 {
+            if check_2(original_target - number, &numbers[..i]).is_some() {
+                return Some(original_target);
+            }
+        }
+        if let Some(head) = disconcat(original_target, *number) {
+            if check_2(head, &numbers[..i]).is_some() {
+                return Some(original_target);
+            }
+        }
+    }
+
+    None
+}
+
+fn disconcat(whole: i64, tail: i64) -> Option<i64> {
+    if tail > whole {
         return None;
     }
 
-    let mut target = original_target;
-    let mut i = line.len() as i32 - 1;
+    let mut whole_s = whole.to_string();
+    let tail_s = tail.to_string();
 
-    while i >= 0 {
-        let modulo = target % line[i as usize];
+    let whole_split = whole_s.split_off(whole_s.len() - tail_s.len());
 
-        if modulo == 0 {
-            target /= line[i as usize];
-
-            let plus_result = check(target - line[i as usize], &line[0..i as usize]);
-
-            if plus_result.is_some() {
-                return plus_result;
-            }
-        } else {
-            target -= line[i as usize];
-        }
-
-        if target < 0 {
-            return None;
-        }
-
-        i -= 1;
-    }
-
-    if target == 0 {
-        Some(original_target)
+    if whole_split == tail_s {
+        Some(whole_s.parse().unwrap_or_default())
     } else {
         None
     }
 }
 
-fn solve_1(input: &str) -> i32 {
+fn solve_2(input: &str) -> i64 {
     let (_, lines) = parse(input).unwrap();
 
-    lines.into_iter().fold(0, |result, line| {
-        dbg!(&line);
-        result + check(line.0, &line.1[..]).unwrap_or_default()
+    lines.into_iter().fold(0, |result, (target, numbers)| {
+        check_2(target, &numbers[..]).unwrap_or_default() + result
     })
 }
 
-fn solve_2(input: &str) {}
-
 fn main() {
     println!("Hello, this is Patrick!");
 
@@ -73,6 +105,7 @@ fn main() {
     println!("The total calibration result is {}", result_1);
 
     let result_2 = solve_2(input);
+    println!("The new total calibration result is {}", result_2);
 }
 
 #[cfg(test)]
@@ -87,5 +120,8 @@ mod tests {
     }
 
     #[test]
-    fn test_2() {}
+    fn test_2() {
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_2(test_input), 11387);
+    }
 }