From 5aa7df1d78d7141c46b8d72f5788e36e330d837d Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Tue, 5 Dec 2017 00:22:25 -0500
Subject: Day 5, part 2

---
 2017/src/bin/day05.rs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

(limited to '2017/src')

diff --git a/2017/src/bin/day05.rs b/2017/src/bin/day05.rs
index b8e21d9..e96138e 100644
--- a/2017/src/bin/day05.rs
+++ b/2017/src/bin/day05.rs
@@ -18,14 +18,42 @@ fn solve1(input: &str) -> u32 {
     unreachable!()
 }
 
+fn solve2(input: &str) -> u32 {
+    let mut jumps: Vec<isize> = input.lines()
+        .map(str::parse)
+        .map(Result::unwrap)
+        .collect();
+
+    let mut index = 0isize;
+    for step in 0.. {
+        if index < 0 || index >= jumps.len() as isize {
+            return step;
+        }
+        let jump = &mut jumps[index as usize];
+        index += *jump;
+        if *jump >= 3 {
+            *jump -= 1;
+        } else {
+            *jump += 1;
+        }
+    }
+    unreachable!()
+}
+
 fn main() {
     let mut input = String::new();
     io::stdin().read_to_string(&mut input).unwrap();
 
     println!("Part 1: {}", solve1(&input));
+    println!("Part 2: {}", solve2(&input));
 }
 
 #[test]
 fn part1() {
     assert_eq!(5, solve1("0\n3\n0\n1\n-3\n"));
 }
+
+#[test]
+fn part2() {
+    assert_eq!(10, solve2("0\n3\n0\n1\n-3\n"));
+}
-- 
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