2 files changed, 103 insertions, 0 deletions
diff --git a/2018/src/day1.rs b/2018/src/day1.rs
new file mode 100644
index 0000000..741f5b3
--- /dev/null
+++ b/2018/src/day1.rs
@@ -0,0 +1,25 @@
+use std::io;
+use std::io::BufRead;
+use std::collections::HashSet;
+
+pub fn main<T: BufRead>(reader: T) -> io::Result<()> {
+    let values: Vec<i64> =
+        reader.lines().map(|l| l.unwrap().parse::<i64>().unwrap()).collect();
+
+    println!("{}", values.iter().sum::<i64>());
+
+    let mut seen = HashSet::new();
+    seen.insert(0);
+
+    let mut res = 0;
+    for val in values.iter().cycle() {
+        res += val;
+        if seen.contains(&res) {
+            println!("{}", res);
+            return Ok(());
+        } else {
+            seen.insert(res);
+        }
+    }
+    unreachable!()
+}
diff --git a/2018/src/main.rs b/2018/src/main.rs
new file mode 100644
index 0000000..7e683ca
--- /dev/null
+++ b/2018/src/main.rs
@@ -0,0 +1,78 @@
+extern crate argparse;
+
+use std::io;
+use std::io::{BufRead, BufReader, Error, ErrorKind};
+use std::fs::File;
+use std::process::exit;
+use argparse::{ArgumentParser, StoreTrue, Store};
+
+mod day1;
+
+fn day_switch<T: BufRead>(day: i32, reader: T) -> io::Result<()> {
+    match day {
+        1 => day1::main(reader),
+        _ => Err(Error::new(ErrorKind::Other, "Invalid day"))
+    }
+}
+
+struct Options {
+    use_stdin: bool,
+}
+
+fn run_day(day: i32, opts: &Options) -> io::Result<()> {
+    if opts.use_stdin {
+        let stdin = io::stdin();
+        day_switch(day, BufReader::new(stdin))
+    } else {
+        match File::open(format!("../input/{}.txt", day)) {
+            Ok(f) => day_switch(day, BufReader::new(f)),
+            Err(_) => Err(Error::new(ErrorKind::Other, format!("No input file for day {}", day)))
+        }
+    }
+}
+
+fn error_handler<F>(func: F) -> io::Result<()>
+        where F: Fn() -> io::Result<()> {
+
+    match func() {
+        Ok(()) => Ok(()),
+        Err(err) => {
+            if err.kind() == ErrorKind::Other {
+                println!("Error: {}", err);
+                exit(1)
+            } else {
+                Err(err)
+            }
+        }
+    }
+}
+
+fn main() -> io::Result<()> {
+    let mut day_string = String::new();
+    let mut options = Options {
+        use_stdin: false
+    };
+
+    {
+        let mut parser = ArgumentParser::new();
+        parser.set_description("AOC 2018 solutions by Tom Smeding");
+        parser.refer(&mut options.use_stdin)
+            .add_option(&["-s", "--stdin"], StoreTrue,
+                        "Read from stdin");
+        parser.refer(&mut day_string)
+            .add_argument("day", Store, "Day to execute");
+        parser.parse_args_or_exit();
+    }
+
+    error_handler(||
+        match day_string.parse::<i32>() {
+            Ok(day) => run_day(day, &options),
+            Err(_) => {
+                for day in 1..1 {
+                    run_day(day, &options)?;
+                }
+                Ok(())
+            }
+        }
+    )
+}