diff --git a/challenges/look-and-say-sequence-conway/solutions/c/function/solution.c b/challenges/look-and-say-sequence-conway/solutions/c/function/solution.c
index 640f6d7..6740664 100644
--- a/challenges/look-and-say-sequence-conway/solutions/c/function/solution.c
+++ b/challenges/look-and-say-sequence-conway/solutions/c/function/solution.c
@@ -10,7 +10,7 @@ int main() {
   size_t string_length = strlen(string);
   char* result = malloc(sizeof(char*) * (string_length + 1));
   for (size_t index = 0; index < string_length; index++) {
-    size_t number_of_appearances = 0;
+    unsigned char number_of_appearances = 0;
     char value_to_search = string[index];
     size_t iteration = index;
     while (iteration < string_length && string[iteration] == value_to_search) {
@@ -18,7 +18,7 @@ int main() {
       iteration++;
     }
     char* number_of_appearances_string = malloc(sizeof(char*) * (string_length + 1));
-    snprintf(number_of_appearances_string, sizeof(result), "%zu", number_of_appearances);
+    snprintf(number_of_appearances_string, sizeof(result), "%hhu", number_of_appearances);
     character_append_many(result, number_of_appearances_string);
     character_append(result, value_to_search);
     index += number_of_appearances - 1;
diff --git a/templates/docker/c/Dockerfile b/templates/docker/c/Dockerfile
index c566c35..27df87d 100644
--- a/templates/docker/c/Dockerfile
+++ b/templates/docker/c/Dockerfile
@@ -2,6 +2,6 @@ FROM gcc:12.2.0
 
 WORKDIR /usr/app
 COPY ./ /usr/app
-RUN gcc ./*.c* -o solution.exe -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c17 -pedantic -pedantic-errors
+RUN gcc ./*.c* -o solution.exe -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c17 -pedantic -pedantic-errors -O3
 
 CMD ["./solution.exe"]
diff --git a/templates/docker/cpp/Dockerfile b/templates/docker/cpp/Dockerfile
index 9170656..49b9b36 100644
--- a/templates/docker/cpp/Dockerfile
+++ b/templates/docker/cpp/Dockerfile
@@ -2,6 +2,6 @@ FROM gcc:12.2.0
 
 WORKDIR /usr/app
 COPY ./ /usr/app
-RUN g++ ./*.cpp* -o solution.exe -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c++17 -pedantic -pedantic-errors
+RUN g++ ./*.cpp* -o solution.exe -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c++17 -pedantic -pedantic-errors -O3
 
 CMD ["./solution.exe"]
diff --git a/templates/docker/dart/Dockerfile b/templates/docker/dart/Dockerfile
index 5eee88c..eacc1ac 100644
--- a/templates/docker/dart/Dockerfile
+++ b/templates/docker/dart/Dockerfile
@@ -1,4 +1,4 @@
-FROM dart:2.17.7
+FROM dart:2.18.1
 
 WORKDIR /usr/app
 COPY ./ /usr/app
diff --git a/templates/docker/java/Dockerfile b/templates/docker/java/Dockerfile
index f12fead..95fd684 100644
--- a/templates/docker/java/Dockerfile
+++ b/templates/docker/java/Dockerfile
@@ -1,4 +1,4 @@
-FROM openjdk:17
+FROM openjdk:19
 
 WORKDIR /usr/app
 COPY ./ /usr/app
diff --git a/templates/docker/rust/Dockerfile b/templates/docker/rust/Dockerfile
index 54ac1d3..e3772b3 100644
--- a/templates/docker/rust/Dockerfile
+++ b/templates/docker/rust/Dockerfile
@@ -1,7 +1,7 @@
-FROM rust:1.63.0
+FROM rust:1.64.0
 
 WORKDIR /usr/app
 COPY ./ /usr/app
-RUN rustc solution.rs
+RUN rustc -C debuginfo=0 -C opt-level=3 -C target-cpu=native solution.rs
 
 CMD ["./solution"]