1 files changed, 25 insertions, 0 deletions
diff --git a/2018/src/day1.rs b/2018/src/day1.rs
new file mode 100644
index 0000000..741f5b3
--- /dev/null
+++ b/2018/src/day1.rs
@@ -0,0 +1,25 @@
+use std::io;
+use std::io::BufRead;
+use std::collections::HashSet;
+
+pub fn main<T: BufRead>(reader: T) -> io::Result<()> {
+    let values: Vec<i64> =
+        reader.lines().map(|l| l.unwrap().parse::<i64>().unwrap()).collect();
+
+    println!("{}", values.iter().sum::<i64>());
+
+    let mut seen = HashSet::new();
+    seen.insert(0);
+
+    let mut res = 0;
+    for val in values.iter().cycle() {
+        res += val;
+        if seen.contains(&res) {
+            println!("{}", res);
+            return Ok(());
+        } else {
+            seen.insert(res);
+        }
+    }
+    unreachable!()
+}