Rust Day 1

Signed-off-by: Tobias Berger <tobi.berger13@gmail.com>

Rust/.gitignore

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+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# These are backup files generated by rustfmt
+**/*.rs.bk

Rust/day1/Cargo.lock

@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "day1"
+version = "0.1.0"

Rust/day1/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "day1"
+version = "0.1.0"
+authors = ["GitHub <noreply@github.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+[[bin]]
+name = "day1"
+path = "main.rs"

Rust/day1/input

@@ -0,0 +1,200 @@
+1822
+1917
+1642
+1617
+1941
+1740
+1529
+1896
+1880
+568
+1897
+1521
+1832
+1936
+611
+1475
+1950
+1895
+1532
+1721
+1498
+1905
+1770
+1845
+2003
+1854
+1705
+1916
+1913
+1956
+1798
+1823
+1955
+1713
+1942
+1710
+1696
+1590
+1966
+1476
+1800
+1672
+1533
+1524
+1957
+1923
+1545
+534
+1707
+1760
+1104
+1471
+1947
+1802
+1525
+1931
+1653
+1608
+1937
+1977
+1598
+1470
+1794
+1488
+1786
+1652
+1482
+1603
+1667
+1245
+1478
+667
+1948
+1885
+547
+1971
+1795
+1910
+1571
+1711
+1727
+1987
+1597
+1586
+1661
+1893
+1873
+1827
+1561
+2006
+1782
+1813
+2000
+1592
+1714
+1849
+1501
+1809
+1751
+1935
+1692
+1697
+1878
+1502
+1738
+1731
+1682
+1690
+1499
+1641
+1925
+1996
+1972
+1886
+1836
+1747
+1841
+1668
+715
+1698
+1859
+1637
+1477
+1785
+1695
+1702
+1944
+1631
+1771
+1623
+1892
+1466
+1834
+1899
+201
+1801
+1978
+1830
+1591
+1673
+1949
+1846
+1677
+1657
+1576
+1817
+1851
+1894
+1754
+1604
+1568
+1730
+1985
+1614
+1980
+1554
+1997
+1960
+1983
+1848
+1883
+1968
+1729
+1716
+628
+1472
+1676
+1943
+1821
+1681
+1619
+1644
+842
+1492
+1633
+1921
+775
+1861
+1584
+1974
+585
+1898
+1560
+1708
+1927
+1563
+1872
+1876
+1865
+1535
+1994
+1756
+1662
+1621
+1993
+1825
+1679
+1959
+1691
+1875

Rust/day1/main.rs

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+use std::fs::File;
+use std::io;
+use std::io::prelude::*;
+use std::path::Path;
+
+fn parse_input<B: BufRead>(buf: B) -> Vec<u64> {
+    buf.lines()
+        .map(|line| {
+            line.expect("Failed to read line.")
+                .parse()
+                .expect("Failed to parse line input.")
+        })
+        .collect()
+}
+
+fn puzzle_a(nums: &[u64]) -> Option<u64> {
+    for a in nums {
+        for b in nums {
+            if a + b == 2020 {
+                return Some(a * b);
+            }
+        }
+    }
+    None
+}
+
+fn puzzle_b(nums: &[u64]) -> Option<u64> {
+    for a in nums {
+        for b in nums {
+            for c in nums {
+                if a + b + c == 2020 {
+                    return Some(a * b * c);
+                }
+            }
+        }
+    }
+
+    None
+}
+
+fn open_file<P>(filename: P) -> io::Result<io::BufReader<File>>
+where
+    P: AsRef<Path>,
+{
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file))
+}
+
+fn main() -> Result<(), &'static str> {
+    let buffer = open_file("input").unwrap();
+    let puzzle_input = parse_input(buffer);
+
+    println!(
+        "Part A:\n{}",
+        puzzle_a(&puzzle_input).expect("No solution for A found.")
+    );
+    println!("--------");
+    println!(
+        "Part B:\n{}",
+        puzzle_b(&puzzle_input).expect("No solution for B found.")
+    );
+
+    Ok(())
+}