[AoC2022] Rust 03

2 files changed, 69 insertions, 1 deletions

diff --git a/AoC2022/03/makefile b/AoC2022/03/makefile
index abcd94b..f781686 100644
--- a/AoC2022/03/makefile
+++ b/AoC2022/03/makefile
@@ -11,4 +11,4 @@
 run:
 	emacs -batch -l ert -l solver.el -f ert-run-tests-batch-and-exit
 	# sbcl --load ~/.sbclrc --script solver.lisp
-	# rustc solver.rs && ./solver
+	rustc solver.rs && ./solver
diff --git a/AoC2022/03/solver.rs b/AoC2022/03/solver.rs
new file mode 100644
index 0000000..21a02c9
--- /dev/null
+++ b/AoC2022/03/solver.rs
@@ -0,0 +1,68 @@
+use std::fs;
+use std::io::{self, BufRead};
+
+fn badge_find(items: &[u8]) -> u64 {
+    items
+        .iter()
+        .fold(0, |badge, &item| badge | 1 << (item - 64))
+}
+
+fn repetition_find(items: &[u8]) -> u32 {
+    let len = items.len() / 2;
+    let left_pack = &items[..len];
+    let right_pack = &items[len..];
+    let (mut left, mut right) = (0u64, 0u64);
+    let mut total = 0;
+
+    for i in 0..len {
+        left |= 1 << left_pack[i] - 64;
+        right |= 1 << right_pack[i] - 64;
+        let cross = left & right;
+        if cross > 0 {
+            total += priority(cross);
+            break;
+        }
+    }
+    total
+}
+fn priority(item: u64) -> u32 {
+    let item = item.trailing_zeros();
+    if item < 32 {
+        item + 26
+    } else {
+        item - 32
+    }
+}
+
+fn solve_prio() -> u32 {
+    let file = fs::File::open("input").unwrap();
+    let lines = io::BufReader::new(file).lines();
+    let mut total = 0;
+    for line in lines {
+        total += repetition_find(line.unwrap().as_bytes());
+    }
+    total
+}
+fn solve_badge() -> u32 {
+    let file = fs::File::open("input").unwrap();
+    let lines = io::BufReader::new(file).lines();
+    let mut total = 0;
+    let mut badge = u64::MAX;
+    let mut grouper = 0;
+
+    for line in lines {
+        let items = line.unwrap();
+        badge &= badge_find(items.as_bytes());
+        grouper += 1;
+        if grouper % 3 == 0 {
+            total += priority(badge);
+            badge = u64::MAX;
+        }
+    }
+    total
+}
+fn main() {
+    assert_eq!(8072, solve_prio());
+    assert_eq!(2567, solve_badge());
+    println!("All test passed.")
+}