From da4f06a825365550e240c93c18557a1d4619da8d Mon Sep 17 00:00:00 2001
From: hal8174 <henning.lindemann@pm.me>
Date: Mon, 2 Dec 2024 21:07:44 +0100
Subject: [PATCH] Fix bug and minor improvements

---
 closest_string/Cargo.toml  |  3 +++
 closest_string/cs0.out     |  2 +-
 closest_string/cs1.out     |  2 +-
 closest_string/cs2.out     |  2 +-
 closest_string/cs3.out     |  2 +-
 closest_string/cs4.out     |  2 +-
 closest_string/src/main.rs | 52 +++++++++++++++++++++++++++++---------
 7 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/closest_string/Cargo.toml b/closest_string/Cargo.toml
index 17a0c76..dea786b 100644
--- a/closest_string/Cargo.toml
+++ b/closest_string/Cargo.toml
@@ -3,5 +3,8 @@ name = "closest_string"
 version = "0.1.0"
 edition = "2021"
 
+[profile.release]
+debug = true
+
 [dependencies]
 clap = { version = "4.5.21", features = ["derive"] }
diff --git a/closest_string/cs0.out b/closest_string/cs0.out
index 768138b..06174f7 100644
--- a/closest_string/cs0.out
+++ b/closest_string/cs0.out
@@ -1 +1 @@
-dbadcabbcbaccbabadbb
+dbaccabbcbacccabadbb
diff --git a/closest_string/cs1.out b/closest_string/cs1.out
index 12f8dc3..ae90d7c 100644
--- a/closest_string/cs1.out
+++ b/closest_string/cs1.out
@@ -1 +1 @@
-acdccadadcbadcdbdaaadacbcdcacbbdcdabbbbddbcbccdbabccccdbbacccdccccacaaddcabaaabbbadacbbddaccccbcccbb
+acdccadbddbadcdbdaaadacbcccacbbdcdabbbbddbcbccdbabccacdbbacccdccccccaaadcabaaabbaadacbbddbacbcbcccbb
diff --git a/closest_string/cs2.out b/closest_string/cs2.out
index 27c30b2..4ffe3bc 100644
--- a/closest_string/cs2.out
+++ b/closest_string/cs2.out
@@ -1 +1 @@
-cdbdbdbababcdaacbabbdadccdbdcdaacdbaacccddcdbbacadcbcacddcddacdaddcbbacbbddcccdcdbcbacccbabbcbbbaaaa
+cdbdbdbdaabcdaaadabbdadccdbdcdaacdbaaaccddcdbbacadabcacddcddaddadddbbacbaddcccdcdbcbbbccbabbcbbbaaaa
diff --git a/closest_string/cs3.out b/closest_string/cs3.out
index c6e27de..74f5781 100644
--- a/closest_string/cs3.out
+++ b/closest_string/cs3.out
@@ -1 +1 @@
-bcdcacdbbbcbbadbbbaabdadcaddcddabbdacddacaaccadcaabdcdddddadacbdcdcbccabbbabdddbacaddcaacaadacbacbdd
+bddcacdabbcbbcdcbbaabdadbaddcddacbdadacaddabcbbcaabbcdddadadacbdcdcbaaccbbabcdabaccddcaaddadacbacbdd
diff --git a/closest_string/cs4.out b/closest_string/cs4.out
index 5f556e7..9811f23 100644
--- a/closest_string/cs4.out
+++ b/closest_string/cs4.out
@@ -1 +1 @@
-bcdbdcdaabaacdbcddadbddcaabcabaadbbccdcbbdbbbccadcaabcbbcdbbcbbbbccacaabbdcdaccbaaaddccbcdcacdcbcacd
+aadbdcdaabcacdbbdbccddcaaadcdbaadbcccdcbbdbbbdcadcadbcbabdbbccbdbccacabbbbcddccaaaadddbbcdcacdcbcacd
diff --git a/closest_string/src/main.rs b/closest_string/src/main.rs
index 13c4429..7dd2611 100644
--- a/closest_string/src/main.rs
+++ b/closest_string/src/main.rs
@@ -20,27 +20,52 @@ fn calculate_hamming_distance(a: &[u8], b: &[u8]) -> usize {
 
 fn simple<'a>(
     strings: &[Vec<u8>],
+    hamming_distances: &mut [u8],
     solution: &'a mut [u8],
-    d: usize,
-    depth: usize,
+    d: u8,
+    depth: u8,
 ) -> Option<&'a [u8]> {
-    let (s, i) = strings
+    let (s, &i) = strings
         .iter()
-        .map(|s| (s, calculate_hamming_distance(s, solution)))
-        .max_by_key(|(_, i)| *i)
+        .zip(hamming_distances.iter())
+        .max_by_key(|(_, &i)| i)
         .unwrap();
 
+    // assert_eq!(i, calculate_hamming_distance(s, solution) as u8);
+
     if i > d + depth {
         return None;
     } else if i <= d {
         return Some(solution);
     }
 
+    if depth == 0 {
+        return None;
+    }
+
     for index in 0..s.len() {
         if s[index] != solution[index] {
             let temp = solution[index];
             solution[index] = s[index];
-            simple(strings, solution, d, depth + 1)?;
+            for j in 0..hamming_distances.len() {
+                if strings[j][index] == temp {
+                    hamming_distances[j] += 1;
+                }
+                if strings[j][index] == s[index] {
+                    hamming_distances[j] -= 1;
+                }
+            }
+            if simple(strings, hamming_distances, solution, d, depth - 1).is_some() {
+                return Some(solution);
+            }
+            for j in 0..hamming_distances.len() {
+                if strings[j][index] == temp {
+                    hamming_distances[j] -= 1;
+                }
+                if strings[j][index] == s[index] {
+                    hamming_distances[j] += 1;
+                }
+            }
             solution[index] = temp;
         }
     }
@@ -48,12 +73,15 @@ fn simple<'a>(
     None
 }
 
-fn closest_string(strings: &[Vec<u8>], d: usize, method: Method) -> Option<Vec<u8>> {
+fn closest_string(strings: &[Vec<u8>], d: u8, method: Method) -> Option<Vec<u8>> {
     match method {
         Method::Simple => {
             let mut s = strings[0].clone();
-
-            if simple(strings, &mut s, d, 0).is_some() {
+            let mut hamming_distances = strings
+                .iter()
+                .map(|l| calculate_hamming_distance(&s, l) as u8)
+                .collect::<Vec<_>>();
+            if simple(strings, &mut hamming_distances, &mut s, d, d).is_some() {
                 Some(s)
             } else {
                 None
@@ -70,7 +98,7 @@ enum Method {
 #[derive(Debug, Parser)]
 struct Args {
     filename: PathBuf,
-    d: Option<usize>,
+    d: Option<u8>,
     #[clap(default_value = "simple")]
     method: Method,
     #[clap(short, long)]
@@ -89,14 +117,14 @@ fn main() {
         eprintln!("{}: {:?}", d, start.elapsed());
         r
     } else if args.reverse {
-        let mut d = strings.len();
+        let mut d = strings.len() as u8;
         let mut last_solution = None;
         loop {
             let start = std::time::Instant::now();
             let r = closest_string(&strings, d, args.method);
             eprintln!("{}: {:?}", d, start.elapsed());
             if let Some(r) = r {
-                d = r.len() - 1;
+                d = r.len() as u8 - 1;
                 last_solution = Some(r);
             } else {
                 break last_solution;