5 files changed, 23 insertions, 33 deletions
diff --git a/src/2020/1/mod.rs b/src/2020/1/mod.rs
index 8aa5290..1c18cad 100644
--- a/src/2020/1/mod.rs
+++ b/src/2020/1/mod.rs
@@ -1,24 +1,22 @@
-pub fn part1() -> anyhow::Result<()> {
+pub fn part1() -> anyhow::Result<i64> {
     let ints = crate::util::read_ints("data/1.txt")?;
     for i in &ints {
         for j in &ints {
             if i + j == 2020 {
-                println!("{} * {} = {}", i, j, i * j);
-                return Ok(());
+                return Ok(i * j);
             }
         }
     }
     Err(anyhow::anyhow!("no numbers summing to 2020 found"))
 }
 
-pub fn part2() -> anyhow::Result<()> {
+pub fn part2() -> anyhow::Result<i64> {
     let ints = crate::util::read_ints("data/1.txt")?;
     for i in &ints {
         for j in &ints {
             for k in &ints {
                 if i + j + k == 2020 {
-                    println!("{} * {} * {} = {}", i, j, k, i * j * k);
-                    return Ok(());
+                    return Ok(i * j * k);
                 }
             }
         }
diff --git a/src/2020/2/mod.rs b/src/2020/2/mod.rs
index a81665b..1026b03 100644
--- a/src/2020/2/mod.rs
+++ b/src/2020/2/mod.rs
@@ -1,4 +1,5 @@
 use anyhow::Context as _;
+use std::convert::TryInto as _;
 use std::io::BufRead as _;
 
 struct Line {
@@ -51,18 +52,16 @@ impl Line {
     }
 }
 
-pub fn part1() -> anyhow::Result<()> {
+pub fn part1() -> anyhow::Result<i64> {
     let lines = read_lines()?;
     let count = lines.iter().filter(|l| l.valid_part_1()).count();
-    println!("{}", count);
-    Ok(())
+    Ok(count.try_into()?)
 }
 
-pub fn part2() -> anyhow::Result<()> {
+pub fn part2() -> anyhow::Result<i64> {
     let lines = read_lines()?;
     let count = lines.iter().filter(|l| l.valid_part_2()).count();
-    println!("{}", count);
-    Ok(())
+    Ok(count.try_into()?)
 }
 
 fn read_lines() -> anyhow::Result<Vec<Line>> {
diff --git a/src/2020/3/mod.rs b/src/2020/3/mod.rs
index 825e31c..81d095a 100644
--- a/src/2020/3/mod.rs
+++ b/src/2020/3/mod.rs
@@ -51,7 +51,7 @@ impl Map {
         &self,
         x_incr: usize,
         y_incr: usize,
-    ) -> anyhow::Result<usize> {
+    ) -> anyhow::Result<i64> {
         let mut trees = 0;
         for r in 0..self.rows() / y_incr {
             let x = r * x_incr;
@@ -64,23 +64,18 @@ impl Map {
     }
 }
 
-pub fn part1() -> anyhow::Result<()> {
+pub fn part1() -> anyhow::Result<i64> {
     let map = read_map()?;
-    println!("{}", map.trees_for_slope(3, 1)?);
-    Ok(())
+    Ok(map.trees_for_slope(3, 1)?)
 }
 
-pub fn part2() -> anyhow::Result<()> {
+pub fn part2() -> anyhow::Result<i64> {
     let map = read_map()?;
-    println!(
-        "{}",
-        map.trees_for_slope(1, 1)?
-            * map.trees_for_slope(3, 1)?
-            * map.trees_for_slope(5, 1)?
-            * map.trees_for_slope(7, 1)?
-            * map.trees_for_slope(1, 2)?
-    );
-    Ok(())
+    Ok(map.trees_for_slope(1, 1)?
+        * map.trees_for_slope(3, 1)?
+        * map.trees_for_slope(5, 1)?
+        * map.trees_for_slope(7, 1)?
+        * map.trees_for_slope(1, 2)?)
 }
 
 fn read_map() -> anyhow::Result<Map> {
diff --git a/src/2020/4/mod.rs b/src/2020/4/mod.rs
index 4b51b29..076a524 100644
--- a/src/2020/4/mod.rs
+++ b/src/2020/4/mod.rs
@@ -3,7 +3,7 @@ use anyhow::Context as _;
 const REQUIRED_KEYS: &[&str] =
     &["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"];
 
-pub fn part1() -> anyhow::Result<()> {
+pub fn part1() -> anyhow::Result<i64> {
     let batch = crate::util::read_file_str("data/4.txt")?;
     let mut valid = 0;
     for passport in parse(&batch)? {
@@ -18,11 +18,10 @@ pub fn part1() -> anyhow::Result<()> {
             valid += 1;
         }
     }
-    println!("{}", valid);
-    Ok(())
+    Ok(valid)
 }
 
-pub fn part2() -> anyhow::Result<()> {
+pub fn part2() -> anyhow::Result<i64> {
     let batch = crate::util::read_file_str("data/4.txt")?;
     let mut valid = 0;
     for passport in parse(&batch)? {
@@ -45,8 +44,7 @@ pub fn part2() -> anyhow::Result<()> {
             valid += 1;
         }
     }
-    println!("{}", valid);
-    Ok(())
+    Ok(valid)
 }
 
 fn parse(
diff --git a/src/2020/mod.rs b/src/2020/mod.rs
index 812a379..8ef019e 100644
--- a/src/2020/mod.rs
+++ b/src/2020/mod.rs
@@ -7,7 +7,7 @@ mod day3;
 #[path = "4/mod.rs"]
 mod day4;
 
-pub fn run(day: u8, puzzle: u8) -> anyhow::Result<()> {
+pub fn run(day: u8, puzzle: u8) -> anyhow::Result<i64> {
     match (day, puzzle) {
         (1, 1) => day1::part1(),
         (1, 2) => day1::part2(),