Day 6, puzzle 2

src/bin/d6p1.rs

@@ -2,7 +2,7 @@ use aoc22::{day6, util};
 
 pub fn main() {
     let input = util::parse_input();
-    let start = day6::parse_datastream(input.as_str());
+    let start = day6::parse_datastream(input.as_str(), 4);
 
-    println!("Datastream starts after {} characters", start + 1);
+    println!("Packet starts after {} characters", start + 1);
 }

src/bin/d6p2.rs

@@ -0,0 +1,8 @@
+use aoc22::{day6, util};
+
+pub fn main() {
+    let input = util::parse_input();
+    let start = day6::parse_datastream(input.as_str(), 14);
+
+    println!("Message starts after {} characters", start + 1);
+}

src/day6.rs

@@ -1,15 +1,15 @@
 use std::collections::{HashSet, VecDeque};
 
-pub fn parse_datastream(stream: &str) -> usize {
+pub fn parse_datastream(stream: &str, n_distinct: usize) -> usize {
     let mut chars: VecDeque<char> = VecDeque::new();
     for (i, char) in stream.chars().enumerate() {
-        if i >= 4 {
+        if i >= n_distinct {
             chars.pop_front();
         }
         chars.push_back(char);
-        if i >= 3 {
+        if i >= n_distinct - 1 {
             let char_set: HashSet<char> = chars.iter().map(char::clone).collect();
-            if char_set.len() == 4 {
+            if char_set.len() == n_distinct {
                 return i;
             }
         }