1 files changed, 71 insertions, 0 deletions
diff --git a/04/src/part-2.rs b/04/src/part-2.rs
new file mode 100644
index 0000000..5c12d21
--- /dev/null
+++ b/04/src/part-2.rs
@@ -0,0 +1,71 @@
+use std::cmp::{Ordering, PartialOrd};
+use std::io::{BufRead};
+use std::str::FromStr;
+
+#[derive(Debug, Eq, PartialEq)]
+struct Interval {
+    a: usize,
+    b: usize
+}
+
+impl PartialOrd for Interval {
+    fn partial_cmp(self: & Self, other: & Self) -> Option<Ordering> {
+        if self == other {
+            Some(Ordering::Equal)
+        }
+        else if self.a >= other.a && self.b <= other.b {
+            Some(Ordering::Less)
+        }
+        else if self.a <= other.a && self.b >= other.b {
+            Some(Ordering::Greater)
+        }
+        else {
+            None
+        }
+    }
+}
+
+impl Interval {
+    fn overlaps(self: & Self, other : & Self) -> bool {
+        self == other
+            || self <= other
+            || self >= other
+            || (self.a <= other.a && self.b >= other.a)
+            || (self.b >= other.b && self.a <= other.b)
+    }
+    
+}
+
+impl FromStr for Interval {
+    type Err = std::string::ParseError;
+
+    fn from_str(s: & str) -> Result<Self, Self::Err> {
+        let mut split = s.split('-');
+        let a: usize = split.next().expect("FIXME: Turn into actual error.").parse().expect("FIXME");
+        let b: usize = split.next().expect("FIXME: Turn into actual error.").parse().expect("FIXME");
+
+        assert!(a <= b);
+        
+        Ok(Self { a: a, b: b })
+    }
+}
+
+fn main() {
+    let stdin = std::io::stdin();
+    let handle = stdin.lock();
+
+    let mut count: usize = 0;
+    
+    for l in handle.lines() {
+        let line = l.unwrap();
+        let mut split = line.split(',');
+        let i_1 = split.next().unwrap().parse::<Interval>().unwrap();
+        let i_2 = split.next().unwrap().parse::<Interval>().unwrap();
+
+        if i_1.overlaps(& i_2) {
+            count += 1;
+        }
+    }
+
+    println!("{}", count);
+}