Implement step 2 for day 1.

2022/day01/Cargo.lock

@@ -5,3 +5,12 @@ version = 3
 [[package]]
 name = "day01"
 version = "0.1.0"
+dependencies = [
+ "sorted-vec",
+]
+
+[[package]]
+name = "sorted-vec"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6734caf0b6f51addd5eeacca12fb39b2c6c14e8d4f3ac42f3a78955c0467458"

2022/day01/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+sorted-vec = "0.8.3"

2022/day01/src/main.rs

@@ -1,14 +1,39 @@
+use std::env;
 use std::io;
 use std::io::prelude::*;
 use std::fs::File;
+use sorted_vec::SortedVec;
 
 fn read_lines(filename: &str) -> io::Result<io::Lines<io::BufReader<File>>> {
     let file = File::open(filename)?;
     Ok(io::BufReader::new(file).lines())
 }
 
+fn get_step() -> i32 {
+    for arg in env::args() {
+        if arg == "2" { return 2 }
+    }
+    return 1
+}
+
+fn update_max(max: &mut SortedVec<i32>, current: i32, step: i32) {
+    if max.is_empty() {
+        max.insert(current);
+        return
+    }
+    if current <= max[0] { return }
+
+    max.insert(current);
+    match step {
+        2 => { if max.len() > 3 { max.remove_index(0); } },
+        _ => { max.remove_index(0); },
+    }
+}
+
 fn main() -> Result<(), io::Error> {
-    let mut max = 0;
+    let step = get_step();
+
+    let mut max: SortedVec<i32> = SortedVec::new();
     let mut current = 0;
 
     for line in read_lines("input.txt")? {
@@ -16,12 +41,12 @@ fn main() -> Result<(), io::Error> {
         current = match text.parse::<i32>() {
             Ok(value) => current + value,
             Err(_) => {
-                if current > max { max = current; }
+                update_max(&mut max, current, step);
                 0
             },
-        };
+        }
     }
 
-    println!("{}", max);
+    println!("{}", max.iter().fold(0i32, |sum, i| sum + (*i as i32)));
     Ok(())
 }