3 files changed, 128 insertions, 0 deletions
diff --git a/2021/src/day01.rs b/2021/src/day01.rs
new file mode 100644
index 0000000..7b1e6a9
--- /dev/null
+++ b/2021/src/day01.rs
@@ -0,0 +1,39 @@
+use std::error::Error;
+use std::fs;
+use std::path::Path;
+
+fn get_input(path: &Path) -> Result<Vec<u16>, Box<dyn Error>> {
+    let data = fs::read_to_string(path)?;
+    Ok(data.lines().filter_map(|x| x.parse::<u16>().ok()).collect())
+}
+
+#[cfg(part1)]
+pub fn solve(path: &Path) -> Result<(), Box<dyn Error>> {
+    let values = get_input(path)?;
+    let mut last = u16::MAX;
+    let mut larger = 0;
+    for v in values {
+        if v > last {
+            larger += 1;
+        }
+
+        last = v;
+    }
+
+    println!("{}", larger);
+    Ok(())
+}
+
+#[cfg(part2)]
+pub fn solve(path: &Path) -> Result<(), Box<dyn Error>> {
+    let values = get_input(path)?;
+    let mut increase = 0;
+    for i in 0..(values.len() - 3) {
+        if values[i] < values[i + 3] {
+            increase += 1;
+        }
+    }
+
+    println!("{}", increase);
+    Ok(())
+}
diff --git a/2021/src/day02.rs b/2021/src/day02.rs
new file mode 100644
index 0000000..e64d2e9
--- /dev/null
+++ b/2021/src/day02.rs
@@ -0,0 +1,67 @@
+use std::str::FromStr;
+use std::error::Error;
+use std::fs;
+use std::path::Path;
+
+#[derive(PartialEq, Debug)]
+enum Command {
+    Forward(i32),
+    Down(i32),
+    Up(i32)
+}
+
+#[derive(Debug)]
+struct ParseCommandError;
+
+impl FromStr for Command {
+    type Err = ParseCommandError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let i = s.find(' ').ok_or(ParseCommandError)?;
+        let num = s[i + 1..].parse::<i32>().map_err(|_| ParseCommandError)?;
+        match &s[..i] {
+            "forward" => Ok(Command::Forward(num)),
+            "down" => Ok(Command::Down(num)),
+            "up" => Ok(Command::Up(num)),
+            _ => Err(ParseCommandError)
+        }
+    }
+}
+
+#[cfg(part1)]
+pub fn solve(path: &Path) -> Result<(), Box<dyn Error>> {
+    let data = fs::read_to_string(path)?;
+    let mut hor = 0;
+    let mut depth = 0;
+    for command in data.lines().filter_map(|x| x.parse::<Command>().ok()) {
+        match command {
+            Command::Forward(v) => hor += v,
+            Command::Down(v) => depth += v,
+            Command::Up(v) => depth -= v
+        }
+    }
+
+    println!("{}", hor * depth);
+    Ok(())
+}
+
+#[cfg(part2)]
+pub fn solve(path: &Path) -> Result<(), Box<dyn Error>> {
+    let data = fs::read_to_string(path)?;
+    let mut aim = 0;
+    let mut hor = 0;
+    let mut depth = 0;
+    for command in data.lines().filter_map(|x| x.parse::<Command>().ok()) {
+        match command {
+            Command::Forward(v) => {
+                hor += v;
+                depth += aim * v;
+            },
+            Command::Down(v) => aim += v,
+            Command::Up(v) => aim -= v
+        }
+    }
+
+    println!("{}", hor * depth);
+    Ok(())
+}
diff --git a/2021/src/main.rs b/2021/src/main.rs
new file mode 100644
index 0000000..ae5f8f2
--- /dev/null
+++ b/2021/src/main.rs
@@ -0,0 +1,22 @@
+use std::env;
+use std::error::Error;
+use std::path::Path;
+
+#[cfg(day01)]
+use day01::solve;
+
+#[cfg(day02)]
+use day02::solve;
+
+#[cfg(day01)]
+mod day01;
+
+#[cfg(day02)]
+mod day02;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let args = env::args().last().unwrap();
+    let path = Path::new(&args);
+
+    solve(path)
+}