Add Solver trait and move common functionality out of concrete solvers

src/solvers/cafeteria.rs

@@ -1,36 +1,30 @@
 use crate::common::interval::Interval;
+use crate::solvers::Solver;
 use std::collections::BTreeSet;
 use std::fs::File;
 use std::io;
-use std::io::BufRead;
-use std::path::Path;
 
 pub struct Cafeteria {
     part1: u64,
     part2: u64,
 }
 
-impl Cafeteria {
-    pub fn new() -> Cafeteria {
-        Cafeteria { part1: 0, part2: 0 }
+impl Solver for Cafeteria {
+    fn get_puzzle_index(&self) -> u8 {
+        5
     }
-
-    pub fn run(&mut self) {
-        println!("--- Day 5: Cafeteria ---");
-
-        // The "../../data" and "../../../data" paths are useful for running the binary from
-        // "target/release/" directory with "data/" directory in package root or parent directory.
-        let paths = vec!["./data", "../data", "../../data", "../../../data"];
-
-        match read_data_file("cafeteria.txt", &paths) {
-            Ok(lines) => {
-                self.process_data(lines);
-                self.print_result();
-            }
-            Err(error) => eprintln!("{}", error),
-        };
+    fn get_puzzle_name(&self) -> &str {
+        "Cafeteria"
+    }
+    fn get_input_filename(&self) -> &str {
+        "cafeteria.txt"
+    }
+    fn get_part1(&self) -> u64 {
+        self.part1
+    }
+    fn get_part2(&self) -> u64 {
+        self.part2
     }
-
     fn process_data(&mut self, mut lines: io::Lines<io::BufReader<File>>) {
         // Builds intervals collection.
         let mut intervals: BTreeSet<Interval> = BTreeSet::new();
@@ -83,41 +77,10 @@ impl Cafeteria {
 
         self.part2 = intervals.iter().map(|x| x.len()).sum();
     }
+}
 
-    fn print_result(&self) {
-        println!("Part 1: {:?}\nPart 2: {:?}\n", self.part1, self.part2);
+impl Cafeteria {
+    pub fn new() -> Cafeteria {
+        Cafeteria { part1: 0, part2: 0 }
     }
 }
-
-fn read_data_file<T>(
-    filename: T,
-    search_paths: &Vec<T>,
-) -> Result<io::Lines<io::BufReader<File>>, String>
-where
-    T: AsRef<Path>,
-{
-    for path in search_paths {
-        if let Ok(lines) = read_lines(path.as_ref().join(&filename)) {
-            return Ok(lines);
-        }
-    }
-
-    let message = search_paths
-        .iter()
-        .map(|path| path.as_ref().join(&filename).display().to_string())
-        .collect::<Vec<_>>()
-        .join("\n");
-    Err(format!(
-        "Cannot open puzzle input file, searched these paths:\n{}",
-        message
-    ))
-}
-
-// This code is taken from https://doc.rust-lang.org/stable/rust-by-example/std_misc/file/read_lines.html
-fn read_lines<T>(filename: T) -> io::Result<io::Lines<io::BufReader<File>>>
-where
-    T: AsRef<Path>,
-{
-    let file = File::open(filename)?;
-    Ok(io::BufReader::new(file).lines())
-}