Add day 7 part 1 and 2

Author: Mr-Ker

input_examples/day07.txt

@@ -0,0 +1,9 @@
+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

src/days.rs

@@ -5,6 +5,7 @@ mod day03;
 mod day04;
 mod day05;
 mod day06;
+mod day07;
 
 use common::generic_day::GenericDay;
 
@@ -21,6 +22,7 @@ pub fn run_day(day: u8, input_folder: String) {
         4 => run_my_day(day04::Day04::new(input_folder)),
         5 => run_my_day(day05::Day05::new(input_folder)),
         6 => run_my_day(day06::Day06::new(input_folder)),
+        7 => run_my_day(day07::Day07::new(input_folder)),
         _ => panic!("Day not found!"),
     }
 }

src/days/day07.rs

@@ -0,0 +1,112 @@
+use std::fs::File;
+use std::io::BufRead;
+use std::io::BufReader;
+
+use super::common::generic_day;
+
+struct EquationInput {
+    result: i64,
+    inputs: Vec<i64>,
+}
+
+pub struct Day07 {
+    input_file: String,
+    equation_inputs: Vec<EquationInput>,
+}
+
+impl Day07 {
+    pub fn new(input_folder: String) -> Day07 {
+        let mut day07: Day07 = Day07 {
+            input_file: format!("{}/day07.txt", input_folder),
+            equation_inputs: Vec::new(),
+        };
+        day07.parse_input();
+        day07
+    }
+
+    fn parse_line(&mut self, line: &str) {
+        let values = line.split(":").collect::<Vec<_>>();
+        self.equation_inputs.push(EquationInput {
+            result: values[0].parse().unwrap(),
+            inputs: values[1]
+                .split_whitespace()
+                .map(|x| x.parse().unwrap())
+                .collect::<Vec<_>>(),
+        });
+    }
+
+    fn parse_input(&mut self) {
+        let _ = BufReader::new(File::open(&self.input_file).unwrap())
+            .lines()
+            .map(|x| x.unwrap())
+            .map(|line| self.parse_line(&line))
+            .collect::<Vec<_>>();
+    }
+
+    fn evaluate_which_equations_could_be_true(
+        &self,
+        operations: Vec<&dyn Fn(i64, i64) -> i64>,
+    ) -> i64 {
+        let mut sum_of_potential_true_equations = 0;
+        for equation_input in &self.equation_inputs {
+            let mut results = vec![equation_input.inputs[0]];
+            for input in equation_input.inputs[1..].iter() {
+                let mut tmp_results: Vec<i64> = Vec::new();
+                for result in results {
+                    for operation in &operations {
+                        tmp_results.push(operation(result, *input));
+                    }
+                }
+                results = tmp_results.clone();
+            }
+
+            for result in results {
+                if equation_input.result == result {
+                    sum_of_potential_true_equations += equation_input.result;
+                    break;
+                }
+            }
+        }
+        sum_of_potential_true_equations
+    }
+}
+
+fn add(a: i64, b: i64) -> i64 {
+    a + b
+}
+
+fn multiply(a: i64, b: i64) -> i64 {
+    a * b
+}
+
+fn concat(a: i64, b: i64) -> i64 {
+    (a.to_string() + &b.to_string()).parse().unwrap()
+}
+
+impl generic_day::GenericDay for Day07 {
+    fn part1(&self) -> i64 {
+        self.evaluate_which_equations_could_be_true(vec![&add, &multiply])
+    }
+
+    fn part2(&self) -> i64 {
+        self.evaluate_which_equations_could_be_true(vec![&add, &multiply, &concat])
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::days::GenericDay;
+
+    #[test]
+    fn result_part1() {
+        let day07: Day07 = Day07::new(String::from("input_examples"));
+        assert_eq!(day07.part1(), 3749);
+    }
+
+    #[test]
+    fn result_part2() {
+        let day07: Day07 = Day07::new(String::from("input_examples"));
+        assert_eq!(day07.part2(), 11387);
+    }
+}