From 09f781d9e52b3c0e9efae5e37a8e7f21058e104a Mon Sep 17 00:00:00 2001
From: logaritmisk <anders.e.olsson@gmail.com>
Date: Thu, 22 Dec 2016 00:25:32 +0100
Subject: [PATCH] 2016/19

---
 2016/19/Cargo.lock  |  4 ++++
 2016/19/Cargo.toml  |  6 ++++++
 2016/19/src/main.rs | 50 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 2016/19/Cargo.lock
 create mode 100644 2016/19/Cargo.toml
 create mode 100644 2016/19/src/main.rs

diff --git a/2016/19/Cargo.lock b/2016/19/Cargo.lock
new file mode 100644
index 0000000..0ff5b3f
--- /dev/null
+++ b/2016/19/Cargo.lock
@@ -0,0 +1,4 @@
+[root]
+name = "19"
+version = "0.1.0"
+
diff --git a/2016/19/Cargo.toml b/2016/19/Cargo.toml
new file mode 100644
index 0000000..1165dc6
--- /dev/null
+++ b/2016/19/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "19"
+version = "0.1.0"
+authors = ["logaritmisk <anders.e.olsson@gmail.com>"]
+
+[dependencies]
diff --git a/2016/19/src/main.rs b/2016/19/src/main.rs
new file mode 100644
index 0000000..1c64250
--- /dev/null
+++ b/2016/19/src/main.rs
@@ -0,0 +1,50 @@
+use std::collections::VecDeque;
+
+
+fn main() {
+    let input = 3018458;
+
+
+    // Part 1.
+    let mut elfs = Vec::new();
+
+    for i in 1..input + 1 {
+        elfs.push(i);
+    }
+
+    while elfs.len() > 1 {
+        let odd = elfs.len() % 2 != 0;
+
+        elfs = elfs.iter()
+            .enumerate()
+            .filter(|&(i, _)| i % 2 == 0)
+            .map(|(_, e)| *e)
+            .collect();
+
+        if elfs.len() > 1 && odd {
+            elfs.remove(0);
+        }
+    }
+
+    println!("winner={:?}", elfs[0]);
+
+
+    // Part 2.
+    let mut elfs = VecDeque::new();
+
+    for i in 1..input + 1 {
+        elfs.push_back(i);
+    }
+
+    while elfs.len() > 1 {
+        let buddy = elfs.len() / 2;
+
+        elfs.remove(buddy);
+
+        let elf = elfs.pop_front().unwrap();
+
+        elfs.push_back(elf);
+    }
+
+    println!("winner={:?}", elfs[0]);
+}