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-rw-r--r--2016/src/bin/day03.rs62
1 files changed, 62 insertions, 0 deletions
diff --git a/2016/src/bin/day03.rs b/2016/src/bin/day03.rs
new file mode 100644
index 0000000..76b5aa5
--- /dev/null
+++ b/2016/src/bin/day03.rs
@@ -0,0 +1,62 @@
+use std::io::{self, Read};
+use std::str::FromStr;
+
+struct Triangle(u32, u32, u32);
+
+impl Triangle {
+    fn valid(&self) -> bool {
+        self.0 + self.1 > self.2
+            && self.1 + self.2 > self.0
+            && self.0 + self.2 > self.1
+    }
+}
+
+impl FromStr for Triangle {
+    type Err = ();
+    fn from_str(s: &str) -> Result<Self, ()> {
+        let mut iter = s.split_whitespace().map(str::parse);
+        match (iter.next(), iter.next(), iter.next()) {
+            (Some(Ok(a)), Some(Ok(b)), Some(Ok(c))) => Ok(Triangle(a, b, c)),
+            _ => Err(()),
+        }
+    }
+}
+
+fn solve1(input: &str) -> usize {
+    input.lines()
+        .map(str::parse)
+        .map(Result::unwrap)
+        .filter(Triangle::valid)
+        .count()
+}
+
+fn solve2(input: &str) -> usize {
+    let triangles: Vec<Triangle> = input.lines()
+        .map(str::parse)
+        .map(Result::unwrap)
+        .collect();
+
+    triangles.chunks(3)
+        .flat_map(|triple| {
+            vec![
+                Triangle(triple[0].0, triple[1].0, triple[2].0),
+                Triangle(triple[0].1, triple[1].1, triple[2].1),
+                Triangle(triple[0].2, triple[1].2, triple[2].2),
+            ]
+        })
+        .filter(Triangle::valid)
+        .count()
+}
+
+fn main() {
+    let mut input = String::new();
+    io::stdin().read_to_string(&mut input).unwrap();
+
+    println!("Part 1: {}", solve1(&input));
+    println!("Part 2: {}", solve2(&input));
+}
+
+#[test]
+fn part1() {
+    assert_eq!(0, solve1("5 10 25"));
+}