Day 1 part 2

2018/src/main.rs

@@ -1,13 +1,40 @@
+use std::collections;
 use std::str;
 
-fn main() {
+fn day1part1() -> i64 {
     let input = include_str!("day1-input.txt");
     let mut freq = 0;
     for line in str::lines(input) {
-        match line.parse::<i32>() {
+        match line.parse::<i64>() {
             Ok(d) => freq += d,
             Err(s) => println!("{}", s),
         }
     }
-    println!("{}", freq);
+    freq
+}
+
+fn day1part2() -> i64 {
+    let input = include_str!("day1-input.txt");
+    let mut freqs = collections::HashSet::new();
+    let mut freq = 0;
+    freqs.insert(freq);
+    loop {
+        for line in str::lines(input) {
+            match line.parse::<i64>() {
+                Ok(d) => {
+                    freq += d;
+                    if freqs.contains(&freq) {
+                        return freq;
+                    }
+                    freqs.insert(freq);
+                }
+                Err(s) => println!("{}", s),
+            }
+        }
+    }
+}
+
+fn main() {
+    println!("{}", day1part1());
+    println!("{}", day1part2());
 }