1 files changed, 63 insertions, 0 deletions
diff --git a/src/bin/2022/day25.rs b/src/bin/2022/day25.rs
new file mode 100644
index 0000000..3149365
--- /dev/null
+++ b/src/bin/2022/day25.rs
@@ -0,0 +1,63 @@
+#![allow(dead_code)]
+#![allow(unused_variables)]
+
+use advent_of_code::prelude::*;
+
+fn from_snafu(line: String) -> i64 {
+    let mut total = 0;
+    for c in line.chars() {
+        let digit = match c {
+            '2' => 2,
+            '1' => 1,
+            '0' => 0,
+            '-' => -1,
+            '=' => -2,
+            _ => panic!("unknown char {}", c),
+        };
+        total *= 5;
+        total += digit;
+    }
+    total
+}
+
+fn to_snafu(mut n: i64) -> String {
+    let mut s = String::new();
+    while n > 0 {
+        let rem = n % 5;
+        let c = match rem {
+            0 => '0',
+            1 => '1',
+            2 => '2',
+            3 => '=',
+            4 => '-',
+            _ => unreachable!(),
+        };
+        s.insert(0, c);
+        n = (n + 2) / 5;
+    }
+    s
+}
+
+pub fn parse(fh: File) -> Result<impl Iterator<Item = String>> {
+    Ok(parse::raw_lines(fh))
+}
+
+pub fn part1(lines: impl Iterator<Item = String>) -> Result<String> {
+    Ok(to_snafu(lines.map(from_snafu).sum()))
+}
+
+pub fn part2(_: impl Iterator<Item = String>) -> Result<i64> {
+    todo!()
+}
+
+#[test]
+fn test() {
+    assert_eq!(
+        part1(parse(parse::data(2022, 25).unwrap()).unwrap()).unwrap(),
+        "2-20=01--0=0=0=2-120"
+    );
+    // assert_eq!(
+    //     part2(parse(parse::data(2022, 25).unwrap()).unwrap()).unwrap(),
+    //     0
+    // );
+}