Day Six

1 files changed, 27 insertions, 0 deletions

diff --git a/2022/rust/day06/src/main.rs b/2022/rust/day06/src/main.rs
new file mode 100644
index 0000000..b5f42cc
--- /dev/null
+++ b/2022/rust/day06/src/main.rs
@@ -0,0 +1,27 @@
+use std::collections::HashSet;
+use std::env;
+use std::fs;
+
+fn main() {
+    let args = env::args().nth(1).expect("missing input");
+    let input = fs::read_to_string(args).unwrap();
+    let signal: Vec<char> = input.trim().chars().collect();
+
+    let depth = 4;
+    for (i, c) in signal.windows(depth).enumerate() {
+        // why can rust not infer the type of HashSet?
+        // https://stackoverflow.com/questions/62949404/
+        if HashSet::<_>::from_iter(c).len() == depth {
+            println!("{}", i + depth);
+            break;
+        }
+    }
+
+    let depth = 14;
+    for (i, c) in signal.windows(depth).enumerate() {
+        if HashSet::<_>::from_iter(c).len() == depth {
+            println!("{}", i + depth);
+            break;
+        }
+    }
+}