Finish set 1.

src/main.rs

@@ -10,4 +10,5 @@ fn main() {
     set1::challenge5();
     set1::challenge6();
     set1::challenge7();
+    set1::challenge8();
 }

src/set1.rs

@@ -171,3 +171,35 @@ pub fn challenge7() {
     let partial_msg = result[..20].to_string();
     println!("[okay] Challenge 7: {}...", partial_msg);
 }
+
+pub fn challenge8() {
+    fn read(path: &str) -> Vec<Bytes> {
+        let file = std::fs::File::open(path).unwrap();
+        let br = BufReader::new(file);
+        br.lines()
+            .map(|line| Bytes::from_hex(&line.unwrap()))
+            .collect()
+    }
+
+    fn rate(Bytes(v): &Bytes, size: usize) -> u32 {
+        let mut rating = 0;
+        let chunks: Vec<&[u8]> = v.chunks(size).collect();
+        for i in 0..chunks.len() {
+            for j in (i + 1)..chunks.len() {
+                rating += Bytes::hemming(&Bytes(chunks[i].to_vec()), &Bytes(chunks[j].to_vec()));
+            }
+        }
+        rating
+    }
+
+    let bytes_vector = read("data/8.txt");
+    let ratings: Vec<u32> = bytes_vector.iter().map(|b| rate(&b, 16)).collect();
+    let min_rating = ratings.iter().min().unwrap();
+    let index = ratings.iter().position(|e| e == min_rating).unwrap();
+    let average = ratings.iter().sum::<u32>() as f32 / ratings.len() as f32;
+    let partial_cipher = bytes_vector[index].to_hex()[..10].to_string();
+    println!(
+        "[okay] Challenge 8: Cipher {} [{}...] with rating {} (average = {}) is the solution.",
+        index, partial_cipher, min_rating, average
+    );
+}