From 9795f16bece9ad501659c344bfec4d1ec44c6f84 Mon Sep 17 00:00:00 2001
From: Alpha Chen <alpha.chen@gmail.com>
Date: Thu, 21 Apr 2016 08:53:01 -0700
Subject: [PATCH] [rust][10.0]

---
 rust/input/day_10.txt |  1 +
 rust/src/day_10.rs    | 59 +++++++++++++++++++++++++++++++++++++++++++
 rust/src/lib.rs       |  1 +
 rust/src/main.rs      |  2 +-
 4 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 rust/input/day_10.txt
 create mode 100644 rust/src/day_10.rs

diff --git a/rust/input/day_10.txt b/rust/input/day_10.txt
new file mode 100644
index 0000000..89172ea
--- /dev/null
+++ b/rust/input/day_10.txt
@@ -0,0 +1 @@
+1113122113
\ No newline at end of file
diff --git a/rust/src/day_10.rs b/rust/src/day_10.rs
new file mode 100644
index 0000000..f7b527a
--- /dev/null
+++ b/rust/src/day_10.rs
@@ -0,0 +1,59 @@
+#[test]
+fn test_day_10() {
+    let mut foo = LookAndSay { seq: vec![2, 1, 1] };
+    assert_eq!(vec![1, 2, 2, 1], foo.next().unwrap());
+
+    foo = LookAndSay { seq: vec![1] };
+    assert_eq!(vec![1, 1], foo.next().unwrap());
+    assert_eq!(vec![2, 1], foo.next().unwrap());
+    assert_eq!(vec![1, 2, 1, 1], foo.next().unwrap());
+    assert_eq!(vec![1, 1, 1, 2, 2, 1], foo.next().unwrap());
+    assert_eq!(vec![3, 1, 2, 2, 1, 1], foo.next().unwrap());
+}
+
+pub fn solve(input: &str) -> usize {
+    let seq = input
+        .chars()
+        .map(|c| c.to_digit(10).unwrap() as usize)
+        .collect::<Vec<usize>>();
+    let mut look_and_say = LookAndSay { seq: seq };
+
+    for _ in 0..40  {
+        look_and_say.next();
+    }
+
+    look_and_say.seq.len()
+}
+
+struct LookAndSay {
+    seq: Vec<usize>,
+}
+
+impl Iterator for LookAndSay {
+    type Item = Vec<usize>;
+
+    fn next(&mut self) -> Option<Vec<usize>> {
+        let mut s = Vec::new();
+
+        let mut digit = self.seq[0];
+        let mut count = 0;
+
+        for &i in &self.seq {
+            if i != digit {
+                s.push(count);
+                s.push(digit);
+
+                digit = i;
+                count = 1;
+            } else {
+                count += 1;
+            }
+        }
+        s.push(count);
+        s.push(digit);
+
+        self.seq = s.clone();
+
+        Some(s)
+    }
+}
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index e80acd3..8cb05f2 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -13,3 +13,4 @@ pub mod day_06;
 pub mod day_07;
 pub mod day_08;
 pub mod day_09;
+pub mod day_10;
diff --git a/rust/src/main.rs b/rust/src/main.rs
index d0e9c96..05febe4 100644
--- a/rust/src/main.rs
+++ b/rust/src/main.rs
@@ -7,5 +7,5 @@ use advent_of_code::*;
 fn main() {
     let mut input = String::new();
     io::stdin().read_to_string(&mut input).ok();
-    println!("{}", day_09::solve(&input));
+    println!("{}", day_10::solve(&input));
 }