1 files changed, 59 insertions, 0 deletions
diff --git a/src/bin/2020/day6.rs b/src/bin/2020/day6.rs
new file mode 100644
index 0000000..114d05f
--- /dev/null
+++ b/src/bin/2020/day6.rs
@@ -0,0 +1,59 @@
+use advent_of_code::prelude::*;
+
+pub fn parse(fh: File) -> Result<impl Iterator<Item = String>> {
+    Ok(parse::raw_lines(fh))
+}
+
+pub fn part1(lines: impl Iterator<Item = String>) -> Result<usize> {
+    let mut yes = HashSet::new();
+    let mut total = 0;
+    for line in lines {
+        if line.is_empty() {
+            total += yes.len();
+            yes = HashSet::new();
+        } else {
+            for c in line.chars() {
+                yes.insert(c);
+            }
+        }
+    }
+    total += yes.len();
+    Ok(total)
+}
+
+pub fn part2(lines: impl Iterator<Item = String>) -> Result<usize> {
+    let mut yes = HashSet::new();
+    for c in 'a'..='z' {
+        yes.insert(c);
+    }
+    let mut total = 0;
+    for line in lines {
+        if line.is_empty() {
+            total += yes.len();
+            yes = HashSet::new();
+            for c in 'a'..='z' {
+                yes.insert(c);
+            }
+        } else {
+            for c in 'a'..='z' {
+                if !line.contains(c) {
+                    yes.remove(&c);
+                }
+            }
+        }
+    }
+    total += yes.len();
+    Ok(total)
+}
+
+#[test]
+fn test() {
+    assert_eq!(
+        part1(parse(parse::data(2020, 6).unwrap()).unwrap()).unwrap(),
+        6930
+    );
+    assert_eq!(
+        part2(parse(parse::data(2020, 6).unwrap()).unwrap()).unwrap(),
+        3585
+    );
+}