From 108ef47eb5fa8d9e4b1342a697088a6c5611c9f0 Mon Sep 17 00:00:00 2001
From: jazzpi <jasper@mezzo.de>
Date: Tue, 13 Dec 2022 13:11:56 +0100
Subject: [PATCH] Day 1, puzzle 2

---
 src/bin/d1p2.rs | 15 +++++++++++++++
 src/lib.rs      |  1 +
 src/util.rs     | 24 ++++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 src/bin/d1p2.rs
 create mode 100644 src/util.rs

diff --git a/src/bin/d1p2.rs b/src/bin/d1p2.rs
new file mode 100644
index 0000000..ccea78f
--- /dev/null
+++ b/src/bin/d1p2.rs
@@ -0,0 +1,15 @@
+use aoc22::day1;
+use aoc22::util;
+
+const N_ELVES: usize = 3;
+
+fn main() {
+    let elves = day1::read_elves();
+
+    let max_vals = util::max_n(elves.as_slice(), N_ELVES).unwrap();
+    println!(
+        "The {} elves with the most calories are carrying {} cal",
+        N_ELVES,
+        max_vals.iter().sum::<u32>()
+    );
+}
diff --git a/src/lib.rs b/src/lib.rs
index 8b2a328..d338c7e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1 +1,2 @@
 pub mod day1;
+pub mod util;
diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..d67db2a
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,24 @@
+pub fn max_n<T: Ord + Copy>(slice: &[T], n: usize) -> Result<Vec<T>, ()> {
+    if n == 0 || n > slice.len() {
+        return Err(());
+    }
+    let mut max_vals = Vec::new();
+    for _ in 0..n {
+        max_vals.push(slice[0]);
+    }
+
+    for val in slice {
+        if val > &max_vals[0] {
+            max_vals[2] = max_vals[1];
+            max_vals[1] = max_vals[0];
+            max_vals[0] = *val;
+        } else if val > &max_vals[1] {
+            max_vals[2] = max_vals[1];
+            max_vals[1] = *val;
+        } else if val > &max_vals[2] {
+            max_vals[2] = *val;
+        }
+    }
+
+    Ok(max_vals)
+}