wip

rust/src/day_02.rs

@@ -0,0 +1,61 @@
+use std::io;
+
+use day::Day;
+
+pub struct Day02 {
+    input: String,
+}
+
+impl Day for Day02 {
+    fn new(input: String) -> Day02 {
+        Day02 { input: input }
+    }
+
+    fn solve(self) -> io::Result<i32> {
+        Ok(1)
+    }
+}
+
+struct Present {
+    length: u32,
+    width: u32,
+    height: u32,
+}
+
+impl Present {
+    fn new(input: String) -> Self {
+        let dimensions = input.split("x")
+                              .map(|d| d.parse::<u32>().unwrap())
+                              .collect::<Vec<u32>>();
+        Present { length: dimensions[0], width: dimensions[1], height: dimensions[2] }
+    }
+
+    fn wrapping_paper(&self) -> u32 {
+        self.surface_area() + self.slack()
+    }
+
+    fn surface_area(&self) -> u32 {
+        self.side_areas().iter().fold(0, |acc, &area| acc + 2 * area)
+    }
+
+    fn slack(&self) -> u32 {
+        *self.side_areas().iter().min().unwrap_or(&0)
+    }
+
+    fn side_areas(&self) -> Vec<u32> {
+        vec![self.length * self.width, self.width * self.height, self.height * self.length]
+    }
+}
+
+#[test]
+fn test_day02() {
+    let mut present = Present::new("2x3x4".to_string());
+    assert_eq!(52, present.surface_area());
+    assert_eq!(6, present.slack());
+    assert_eq!(58, present.wrapping_paper());
+
+    present = Present::new("1x1x10".to_string());
+    assert_eq!(42, present.surface_area());
+    assert_eq!(1, present.slack());
+    assert_eq!(43, present.wrapping_paper());
+}

rust/src/lib.rs

@@ -2,4 +2,6 @@ pub use day::Day;
 mod day;
 
 pub use day_01::Day01;
+pub use day_02::Day02;
 mod day_01;
+mod day_02;

rust/src/main.rs

@@ -19,7 +19,7 @@ fn read_input(filename: &str) -> Result<String, io::Error> {
 }
 
 fn main() {
-    let input = read_input("day_01").unwrap();
+    let input = read_input("day_02").unwrap();
-    let day = Day01::new(input);
+    let day = Day02::new(input);
     println!("{}", day.solve().unwrap());
 }