Add solution to day 9 part 1.

Part 2 is mean.

2016/day-09/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day-09"
+version = "0.1.0"
+authors = ["Bert Peters <bert.ljpeters@gmail.com>"]
+
+[dependencies]
+regex = "^0.1"

2016/day-09/src/main.rs

@@ -0,0 +1,41 @@
+extern crate regex;
+
+use regex::Regex;
+use std::env;
+use std::io::prelude::*;
+use std::fs::File;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    let mut f = File::open(&args[1]).expect("Could not open file");
+
+    let mut data = String::new();
+    f.read_to_string(&mut data).expect("How can I not read this?");
+
+    let content = data.trim();
+
+    let r = Regex::new(r"\((\d+)x(\d+)\)").expect("Failed to compile regex");
+
+    let mut len = 0;
+    let mut pos = 0;
+
+    loop {
+        let todo = &content[pos..];
+        match r.captures(todo) {
+            Some(captures) => {
+                let (start, _) = r.find(todo).unwrap();
+                let (length, amount) = (captures[1].parse::<i64>().unwrap(), captures[2].parse::<i64>().unwrap());
+                pos += start + captures[0].len() as usize + length as usize;
+                len += start as i64 + length as i64 * amount;
+            },
+            None => {
+                // No more markers remaining, just append the rest
+                len += content.len() as i64 - pos as i64;
+                break;
+            },
+        }
+    }
+
+    println!("Decoded text is {} long", len);
+
+}