From c2297ba8495a44b75ce6cf112bf72ee472637e68 Mon Sep 17 00:00:00 2001
From: Antoine Martin <antoine97.martin@gmail.com>
Date: Tue, 3 Dec 2019 17:00:25 +0100
Subject: [PATCH] 2015: day05: part 2

---
 aoc2015/src/day05.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/aoc2015/src/day05.rs b/aoc2015/src/day05.rs
index e7a9d6e..c54e60d 100644
--- a/aoc2015/src/day05.rs
+++ b/aoc2015/src/day05.rs
@@ -4,6 +4,7 @@ const INPUT: &str = include_str!("../input/day05.txt");
 
 pub fn run() -> Result<()> {
     println!("part 1: {}", part1(INPUT));
+    println!("part 2: {}", part2(INPUT));
 
     Ok(())
 }
@@ -43,6 +44,33 @@ fn part1(input: &str) -> usize {
         .count()
 }
 
+fn part2(input: &str) -> usize {
+    input
+        .lines()
+        .map(|line| line.trim_end())
+        .filter(|line| {
+            for i in 0..(line.chars().count() - 3) {
+                let seq = &line[i..(i + 2)];
+                let line = &line[(i + 2)..];
+                if line.find(seq).is_some() {
+                    return true;
+                }
+            }
+
+            false
+        })
+        .filter(|line| {
+            for i in 0..(line.chars().count() - 2) {
+                if line.chars().nth(i).unwrap() == line.chars().nth(i + 2).unwrap() {
+                    return true;
+                }
+            }
+
+            false
+        })
+        .count()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -60,4 +88,17 @@ mod tests {
     fn part1_real() {
         assert_eq!(part1(INPUT), 258);
     }
+
+    #[test]
+    fn part2_provided() {
+        assert_eq!(part2("qjhvhtzxzqqjkmpb"), 1);
+        assert_eq!(part2("xxyxx"), 1);
+        assert_eq!(part2("uurcxstgmygtbstg"), 0);
+        assert_eq!(part2("ieodomkazucvgmuy"), 0);
+    }
+
+    #[test]
+    fn part2_real() {
+        assert_eq!(part2(INPUT), 53);
+    }
 }