feat(07/2024): solve first part

Author: manhunto

readme.md

@@ -17,6 +17,7 @@
 | [Day 4: Ceres Search](src/solutions/year2024/day04.rs)       |   ⭐⭐   |            8.620 |            6.918 |
 | [Day 5: Print Queue](src/solutions/year2024/day05.rs)        |   ⭐⭐   |            3.151 |           11.874 |
 | [Day 6: Guard Gallivant](src/solutions/year2024/day06.rs)    |   ⭐    |            8.738 |                  |
+| [Day 7: Bridge Repair](src/solutions/year2024/day07.rs)      |   ⭐    |           18.503 |                  |
 
 # 2023
 

src/solutions/year2024/day07.rs

@@ -1,25 +1,72 @@
 use crate::solutions::Solution;
+use itertools::Itertools;
 pub struct Day07;
 
 impl Solution for Day07 {
-    fn part_one(&self, _input: &str) -> String {
-        String::from('0')
+    fn part_one(&self, input: &str) -> String {
+        input
+            .lines()
+            .map(|l| {
+                let (left, right) = l.split(": ").collect_tuple().unwrap();
+                let test_value: usize = left.parse().unwrap();
+                let mut numbers: Vec<usize> = right
+                    .split_whitespace()
+                    .map(|s| s.parse().unwrap())
+                    .collect();
+
+                let current = numbers.remove(0);
+                let value = Self::solve(test_value, current, numbers.clone());
+
+                if value {
+                    return test_value;
+                }
+
+                0
+            })
+            .sum::<usize>()
+            .to_string()
     }
 
     fn part_two(&self, _input: &str) -> String {
         String::from('0')
     }
 }
 
+impl Day07 {
+    fn solve(expected: usize, current: usize, number_lefts: Vec<usize>) -> bool {
+        let mut numbers = number_lefts.clone();
+
+        if numbers.is_empty() {
+            return expected == current;
+        }
+
+        let next = numbers.remove(0);
+
+        let current_add = current + next;
+        let current_multiply = current * next;
+
+        Self::solve(expected, current_add, numbers.clone())
+            || Self::solve(expected, current_multiply, numbers)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::solutions::year2024::day07::Day07;
     use crate::solutions::Solution;
 
-    const EXAMPLE: &str = r#""#;
+    const EXAMPLE: &str = r#"190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20"#;
 
     #[test]
     fn part_one_example_test() {
-        assert_eq!("0", Day07.part_one(EXAMPLE));
+        assert_eq!("3749", Day07.part_one(EXAMPLE));
     }
 }