Solve Part 2

src/main.rs

@@ -7,6 +7,7 @@ fn has_duplicates(slice: &[char]) -> bool
     (1..slice.len()).any(|i| slice[i..].contains(&slice[i - 1]))
 }
 
+#[allow(dead_code)]
 fn part1()
 {
     let mut last_char = 0usize;
@@ -36,6 +37,37 @@ fn part1()
     }
 }
 
-fn main() {
+fn part2()
-    part1();
+{
+    let mut last_char = 0usize;
+
+    let mut buffer: Vec<char> = Vec::with_capacity(14);
+
+    for c in DATA.chars()
+    {
+        last_char += 1;
+
+        if buffer.len() == 14
+        {
+            buffer.remove(0);
+        }
+
+        buffer.push(c);
+
+        if last_char < 14 {
+            continue;
+        }
+
+        if !has_duplicates(buffer.as_slice())
+        {
+            println!("First start-of-packet marker at {}", last_char);
+            break;
+        }
+    }
+}
+
+
+fn main() {
+    //part1();
+    part2();
 }