Add 9 first days

6-custom_customs/src/main.rs

@@ -0,0 +1,81 @@
+use std::{collections::HashSet, todo};
+
+use itertools::Itertools;
+
+fn count_scores(input: &str) -> Vec<usize> {
+    input
+        .split("\n\n")
+        .map(|l| l.chars()
+                       .unique()
+                       .filter(|&c| c != '\n')
+                       .count())
+        .collect()
+}
+
+fn count_scores_v2(input: &str) -> Vec<usize> {
+    input
+    .split("\n\n")
+    .map(|group| {
+        group
+            .lines()
+            .map(|l| l.chars().collect::<HashSet<char>>())
+            .fold1(|acc: HashSet<char>, hset| {
+                acc.intersection(&hset).cloned().collect()
+            })
+            .unwrap()
+            .len()
+    })
+    .collect()
+}
+
+fn main() {
+    let input = include_str!("../data/input.txt");
+    let scores = count_scores(input);
+    println!("Sum of scores : {}", scores.iter().sum::<usize>());
+    println!("Sum of scores v2 : {}", count_scores_v2(input).iter().sum::<usize>())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_count_scores() {
+        let input = r#"abc
+
+a
+b
+c
+
+ab
+ac
+
+a
+a
+a
+a
+
+b"#;
+        assert_eq!(count_scores(input).iter().sum::<usize>(), 11)
+    }
+
+    #[test]
+    fn test_count_scores_v2() {
+        let input = r#"abc
+
+a
+b
+c
+
+ab
+ac
+
+a
+a
+a
+a
+
+b"#;
+        assert_eq!(count_scores_v2(input).iter().sum::<usize>(), 6);
+    }
+}