2020: day01: part 1

Cargo.lock

@@ -29,6 +29,14 @@ dependencies = [
  "criterion",
 ]
 
+[[package]]
+name = "aoc2020"
+version = "0.1.0"
+dependencies = [
+ "aoc",
+ "criterion",
+]
+
 [[package]]
 name = "atty"
 version = "0.2.14"

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace]
 members = ["aoc*"]
 
-default-members = ["aoc2019"]
+default-members = ["aoc2020"]
 
 [profile.release]
 debug = true

aoc2020/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "aoc2020"
+version = "0.1.0"
+authors = ["Antoine Martin <antoine97.martin@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dev-dependencies]
+
+criterion = "0.3"
+
+[dependencies]
+
+aoc = { path = "../aoc" }
+
+[lib]
+path = "src/lib.rs"
+bench = false
+
+[[bin]]
+name = "aoc2020"
+path = "src/main.rs"
+bench = false
+
+[[bench]]
+name = "bench"
+harness = false

aoc2020/benches/bench.rs

@@ -0,0 +1,14 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+
+use aoc2020::day01;
+
+fn aoc2020_all(c: &mut Criterion) {
+    c.bench_function("day01", |b| b.iter(|| day01::run().unwrap()));
+}
+
+criterion_group! {
+    name = all_days;
+    config = Criterion::default().sample_size(30);
+    targets = aoc2020_all
+}
+criterion_main!(all_days);

aoc2020/input/day01.txt

@@ -0,0 +1,200 @@
+1935
+1956
+1991
+1425
+1671
+1537
+1984
+1569
+1873
+1840
+1720
+1937
+1823
+1625
+1727
+1812
+1714
+1900
+1939
+1931
+1951
+1756
+1942
+1611
+1979
+1930
+1996
+2000
+1544
+1780
+1687
+1760
+1836
+1814
+1691
+1817
+1964
+1899
+1577
+1547
+866
+1560
+1988
+1601
+1970
+1738
+1507
+1667
+1851
+1933
+1515
+1856
+1969
+1860
+1801
+2007
+1866
+1800
+1749
+1843
+1711
+1495
+1905
+763
+1672
+1858
+1987
+1492
+1849
+1993
+1737
+1874
+1658
+1810
+1665
+1768
+1950
+1879
+1816
+1868
+1995
+1763
+1783
+1833
+1968
+1847
+1748
+1725
+1891
+1755
+286
+1976
+1977
+1655
+1808
+1986
+1779
+1861
+1953
+1888
+1792
+1811
+1872
+1790
+1839
+1985
+1827
+1842
+1925
+1735
+1635
+1821
+1820
+1973
+1531
+1770
+59
+1846
+1932
+1907
+1730
+933
+1395
+1753
+1751
+361
+1530
+1782
+1087
+1589
+1929
+1795
+1815
+1732
+1765
+1877
+1722
+526
+1709
+1789
+1892
+1913
+1662
+1809
+1670
+1947
+1835
+1587
+1758
+1982
+2009
+1757
+670
+1983
+1524
+1878
+1796
+1952
+566
+1922
+1882
+1870
+1799
+1731
+1724
+1805
+2003
+1596
+1566
+1853
+1911
+1857
+1739
+1744
+1627
+1729
+1745
+1845
+1582
+1884
+1883
+1941
+1764
+1685
+1791
+1837
+1697
+1742
+1781
+1948
+1876
+1989
+1643
+1871
+1906
+1726
+1958
+1502
+1927
+1946

aoc2020/src/day01.rs

@@ -0,0 +1,56 @@
+use std::fmt::Write;
+
+use aoc::{err, Result};
+
+const INPUT: &str = include_str!("../input/day01.txt");
+
+pub fn run() -> Result<String> {
+    let mut res = String::with_capacity(128);
+
+    writeln!(res, "part 1: {}", part1(INPUT)?)?;
+
+    Ok(res)
+}
+
+fn part1(input: &str) -> Result<u64> {
+    let entries = input
+        .lines()
+        .map(|line| line.parse::<u64>().map_err(|e| err!("{}", e)))
+        .collect::<Result<Vec<u64>>>()?;
+
+    let (a, b) = find_2020_sum(&entries)?;
+
+    Ok(a * b)
+}
+
+fn find_2020_sum(entries: &[u64]) -> Result<(u64, u64)> {
+    for i in 0..(entries.len()) {
+        for j in 0..entries.len() {
+            if i == j {
+                continue;
+            }
+            if entries[i] + entries[j] == 2020 {
+                return Ok((entries[i], entries[j]));
+            }
+        }
+    }
+
+    Err(err!("couldn't find 2 elements that sum to 2020"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_provided() {
+        let (a, b) = find_2020_sum(&vec![1721, 979, 366, 299, 675, 1456]).unwrap();
+        assert_eq!(a, 1721);
+        assert_eq!(b, 299);
+    }
+
+    #[test]
+    fn part1_real() {
+        assert_eq!(part1(INPUT).unwrap(), 1014171);
+    }
+}

aoc2020/src/lib.rs

@@ -0,0 +1 @@
+pub mod day01;

aoc2020/src/main.rs

@@ -0,0 +1,10 @@
+use aoc::DayFunc;
+use aoc::Result;
+
+use aoc2020::day01;
+
+fn main() -> Result<()> {
+    let days: &[DayFunc] = &[day01::run];
+
+    aoc::run(days)
+}