finished day 1

src/bin/1.rs

@@ -0,0 +1,57 @@
+/*
+--- Day 1: Report Repair ---
+
+After saving Christmas five years in a row, you've decided to take a vacation at a nice resort on a
+tropical island. Surely, Christmas will go on without you.
+
+The tropical island has its own currency and is entirely cash-only. The gold coins used there have
+a little picture of a starfish; the locals just call them stars. None of the currency exchanges
+seem to have heard of them, but somehow, you'll need to find fifty of these coins by the time you
+arrive so you can pay the deposit on your room.
+
+To save your vacation, you need to get all fifty stars by December 25th.
+
+Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent
+calendar; the second puzzle is unlocked when you complete the first. Each puzzle grants one star.
+Good luck!
+
+Before you leave, the Elves in accounting just need you to fix your expense report (your puzzle
+input); apparently, something isn't quite adding up.
+
+Specifically, they need you to find the two entries that sum to 2020 and then multiply those two
+numbers together.
+
+For example, suppose your expense report contained the following:
+
+1721
+979
+366
+299
+675
+1456
+In this list, the two entries that sum to 2020 are 1721 and 299. Multiplying them together
+produces 1721 * 299 = 514579, so the correct answer is 514579.
+
+Of course, your expense report is much larger. Find the two entries that sum to 2020; what
+do you get if you multiply them together?
+*/
+
+use std::{fs::{File}, io};
+use std::collections::HashSet;
+use std::io::{BufRead, BufReader};
+
+fn main() -> io::Result<()> {
+    //let contents = fs::read_to_string("1.input").expect("Couldn't read \"1.input\"");
+    let file = File::open("1.input")?;
+    let reader = BufReader::new(file);
+
+    let mut list: Vec<i32> = Vec::new();
+    let mut set: HashSet<i32> = HashSet::new();
+
+    for line in reader.lines() {
+        let value = line.unwrap().parse::<i32>().unwrap();
+        list.push(value);
+        set.insert(value);
+    }
+    Ok(())
+}