Day 8 part 1

2019/src/bin/day8.rs

@@ -0,0 +1,26 @@
+use std::{fs, io};
+
+const WIDTH: usize = 25;
+const HEIGHT: usize = 6;
+
+fn main() -> io::Result<()> {
+    let data = fs::read_to_string("input/day8.txt")?;
+    let image = data.trim().chars().collect::<Vec<_>>();
+
+    let layers = image.chunks(WIDTH * HEIGHT).collect::<Vec<_>>();
+    let layer = layers
+        .iter()
+        .min_by_key(|layer| count_digits(layer, '0'))
+        .unwrap();
+
+    let ones = count_digits(layer, '1');
+    let twos = count_digits(layer, '2');
+
+    println!("Part 1: {}", ones * twos);
+
+    Ok(())
+}
+
+fn count_digits(layer: &[char], digit: char) -> usize {
+    layer.iter().filter(|&&c| c == digit).count()
+}