From e03fc564c131fef7e26852b0c1f689a2c061ab3a Mon Sep 17 00:00:00 2001
From: Sijmen Schoon <me@sijmenschoon.nl>
Date: Tue, 15 Dec 2020 18:08:40 +0100
Subject: [PATCH] Rust: day 15 first working

---
 rust/src/main.rs | 105 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 104 insertions(+), 1 deletion(-)

diff --git a/rust/src/main.rs b/rust/src/main.rs
index 8521e2a..32aadf4 100644
--- a/rust/src/main.rs
+++ b/rust/src/main.rs
@@ -377,6 +377,94 @@ mod day08 {
     }
 }
 
+mod day09 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day10 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day11 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day12 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day13 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day14 {
+    use std::time::Duration;
+
+    pub fn run(_: bool) -> Duration {
+        Duration::new(0, 0)
+    }
+}
+
+mod day15 {
+    use std::time::{Duration, Instant};
+
+    const END: usize = 30_000_000;
+    pub fn run(print: bool) -> Duration {
+        let input: Vec<usize> = "0,1,5,10,3,12,19"
+            .split(",")
+            .map(|i| i.parse().unwrap())
+            .collect();
+        let instant = Instant::now();
+
+        let mut history = vec![0; END];
+        let mut last = input[0];
+        for turn in 0..input.len() {
+            history[last] = turn;
+            last = input[turn];
+        }
+
+        for turn in input.len()..2020 {
+            let stored = history[last];
+            history[last] = turn;
+            last = if stored == 0 { 0 } else { turn - stored };
+        }
+        if print {
+            println!("Part 1: {}", last);
+        }
+
+        for turn in 2020..END {
+            let stored = history[last];
+            history[last] = turn;
+            last = if stored == 0 { 0 } else { turn - stored };
+        }
+        if print {
+            println!("Part 2: {}", last);
+        }
+
+        instant.elapsed()
+    }
+}
+
 fn main() {
     let days = [
         day01::run,
@@ -387,6 +475,13 @@ fn main() {
         day06::run,
         day07::run,
         day08::run,
+        day09::run,
+        day10::run,
+        day11::run,
+        day12::run,
+        day13::run,
+        day14::run,
+        day15::run,
     ];
 
     if let Some(day) = std::env::args().nth(1) {
@@ -395,10 +490,18 @@ fn main() {
             days[day - 1](true);
         }
     } else {
-        let repetitions = 2000;
         let mut total = Duration::new(0, 0);
 
         for day in 0..days.len() {
+            let first_run = days[day](false);
+            if first_run.as_nanos() == 0 {
+                println!("Day {:>2}: skipped", day);
+                continue;
+            }
+
+            let repetitions =
+                5000.min((Duration::new(5, 0).as_nanos() / first_run.as_nanos()) as u32);
+
             let mut elapsed = Duration::new(0, 0);
             for _ in 0..repetitions {
                 elapsed += days[day](false) / repetitions;