1 files changed, 49 insertions, 0 deletions
diff --git a/06/src/part-2.rs b/06/src/part-2.rs
new file mode 100644
index 0000000..37d095e
--- /dev/null
+++ b/06/src/part-2.rs
@@ -0,0 +1,49 @@
+use std::io::{BufRead};
+
+#[derive(Clone, Copy)]
+struct FishSchool {
+    state: u64,
+    size: usize
+}
+
+pub fn main() {
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() != 2 { panic!("Need exactly 1 argument"); }
+    let num_days: usize = args[1].parse().expect("Need number of days as argument");
+    
+    let mut stdin = std::io::stdin();
+    let mut handle = stdin.lock();
+
+    let input: String = {
+        let mut buf = String::new();
+        handle.read_line(&mut buf).unwrap();
+        String::from(buf.trim_end())
+    };
+
+    let mut schools: Vec<FishSchool> = input.split(',').map(|w| FishSchool {
+        state: w.parse().expect("Malformed input"),
+        size: 1} ).collect();
+
+    for i in 0..num_days {
+        let mut new_fish_count: usize = 0;
+        for school in (&mut schools).into_iter() {
+            if school.state == 0 {
+                new_fish_count += school.size;
+                school.state = 6;
+            }
+            else { school.state -= 1; }
+        }
+        schools.push(FishSchool { state: 8, size: new_fish_count });
+
+        /*
+        print!("After day {:>width$}: ", i, width = format!("{}", num_days).len());
+        for school in (& schools).into_iter() {
+            for _ in 0..school.size { print!("{} ", school.state); }
+        }
+        println!("");
+        */
+    }
+
+    let n: usize = schools.into_iter().map(|school| school.size).sum();
+    println!("After {} days there are {} fishies", num_days, n);
+}