d6p1

day6/src/main.rs

@@ -0,0 +1,26 @@
+use std::env;
+use std::fs::File;
+use std::io::{BufReader, Read};
+
+fn main() {
+    let file = File::open(&env::args().nth(1).unwrap()).unwrap();
+    let reader = BufReader::new(file);
+
+    let (mut x1, mut x2, mut x3) = (0, 0, 0);
+    let mut i = 0;
+    for byte in reader.bytes() {
+        i += 1;
+        let c = byte.unwrap();
+        if c != x1 && c != x2 && c != x3
+                && x1 != x2 && x1 != x3 && x2 != x3
+                && x1 != 0 {
+            println!("{}", i);
+            break;
+        } else {
+            x1 = x2;
+            x2 = x3;
+            x3 = c;
+        }
+    }
+}
+