Add day 1

Author: Linus Kardell

.gitignore

@@ -1,6 +1,6 @@
 # Generated by Cargo
 # will have compiled files and executables
-/target/
+target/
 
 # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
 # More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

Day1_input.txt

@@ -0,0 +1,200 @@
+1688
+1463
+1461
+1842
+1441
+1838
+1583
+1891
+1876
+1551
+1506
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+1493
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+1564
+1572

day1a/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "day1a"
+version = "0.1.0"
+authors = ["linus"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day1a/src/main.rs

@@ -0,0 +1,16 @@
+use std::io;
+use std::io::Read;
+
+fn main() {
+    let mut input = String::new();
+    io::stdin().read_to_string(&mut input).unwrap();
+    let numbers: Vec<u32> = input.lines().map(|x| x.parse().unwrap()).collect();
+    'outer: for (n, i) in numbers.iter().enumerate() {
+        for j in numbers.iter().skip(n + 1) {
+            if i + j == 2020 {
+                println!("{}", i * j);
+                break 'outer;
+            }
+        }
+    }
+}

day1b/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "day1b"
+version = "0.1.0"
+authors = ["linus"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day1b/src/main.rs

@@ -0,0 +1,18 @@
+use std::io;
+use std::io::Read;
+
+fn main() {
+    let mut input = String::new();
+    io::stdin().read_to_string(&mut input).unwrap();
+    let numbers: Vec<u32> = input.lines().map(|x| x.parse().unwrap()).collect();
+    'outer: for (n, i) in numbers.iter().enumerate() {
+        for (m, j) in numbers.iter().enumerate().skip(n + 1) {
+            for k in numbers.iter().skip(m + 1) {
+                if i + j + k == 2020 {
+                    println!("{}", i * j * k);
+                    break 'outer;
+                }
+            }
+        }
+    }
+}