4 files changed, 101 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3e89409
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+target/
+**/*.rs.bk
+input.txt
diff --git a/day2/Cargo.lock b/day2/Cargo.lock
new file mode 100644
index 0000000..3faaae6
--- /dev/null
+++ b/day2/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "day2"
+version = "0.1.0"
+
diff --git a/day2/Cargo.toml b/day2/Cargo.toml
new file mode 100644
index 0000000..4848f85
--- /dev/null
+++ b/day2/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day2"
+version = "0.1.0"
+authors = ["Jan Tuomi <jan.tuomi@eficode.com>"]
+
+[dependencies]
diff --git a/day2/src/main.rs b/day2/src/main.rs
new file mode 100644
index 0000000..9a68b3a
--- /dev/null
+++ b/day2/src/main.rs
@@ -0,0 +1,88 @@
+use std::env;
+use std::io::BufReader;
+use std::io::BufRead;
+use std::fs::File;
+use std::process;
+use std::collections::HashSet;
+
+fn main() {
+  let args: Vec<String> = env::args().collect();
+  if args.len() != 2 {
+    println!("Wrong number of arguments. Provide just a file name.");
+    process::exit(1);
+  }
+  let filename = &args[1];
+  println!("Using file {} as input.", filename);
+  let f = match File::open(filename) {
+    Ok(file) => file,
+    Err(e) => {
+      println!("Failed to open file {}. {:?}", filename, e);
+      process::exit(1);
+    }
+  };
+  let file = BufReader::new(&f);
+
+  let mut strings: Vec<String> = Vec::new();
+  // exercise 1
+  for line in file.lines() {
+    let l = line.unwrap();
+    strings.push(l);
+  }
+
+  // exercise 1
+  let mut doubles = 0;
+  let mut triples = 0;
+
+  for string in &strings {
+    let chars: Vec<char> = string.chars().collect();
+    let mut is_double = false;
+    let mut is_triple = false;
+    for ch in &chars {
+      let exacts: Vec<&char> = chars.iter().filter(|&c| c == ch).collect();
+      let count = exacts.len();
+      match count {
+        2 => { is_double = true; }
+        3 => { is_triple = true; }
+        _ => {}
+      }
+    }
+
+    if is_double {
+      doubles += 1;
+    }
+
+    if is_triple {
+      triples += 1;
+    }
+  }
+
+  println!("Doubles: {}", doubles);
+  println!("Triples: {}", triples);
+  let checksum = doubles * triples;
+  println!("Checksum: {}", checksum);
+
+  // exercise 2
+  let n = strings.len();
+  for i in 0..n {
+    let string = &strings[i];
+    let s_chars: Vec<char> = string.chars().collect();
+
+    let char_count = s_chars.len();
+    for j in (i + 1)..n {
+      let other = &strings[j];
+      let o_chars: Vec<char> = other.chars().collect();
+
+      let mut commons: Vec<&char> = Vec::new();
+      for k in 0..char_count {
+        if s_chars[k] == o_chars[k] {
+          commons.push(&s_chars[k]);
+        }
+      }
+
+      if commons.len() == char_count - 1 {
+        let sol: String = commons.into_iter().collect();
+        println!("Solution: {}", sol);
+      }
+    }
+  }
+}