Expand cross-language notes and strengthen core smoke

Author: lucasbellesi

languages/cpp/01-foundations/arrays-and-vectors/README.md

@@ -38,6 +38,12 @@ g++ -std=c++17 -Wall -Wextra -pedantic example/vector-filter.cpp -o arrays_and_v
 - Mixing signed and unsigned indexes carelessly.
 - Forgetting to validate `n` before reading values.
 
+## Cross-Language Notes
+
+- Compared with the C++ version, each track solves the same sequence problems with a different default dynamic-array model.
+- The key comparison is where bounds safety, resizing behavior, and iteration ergonomics come from in each language.
+- This module is most useful when you notice how similar tasks feel different under `vector`, `List<T>`, slices, Python lists, and TypeScript arrays.
+
 ## Exercise Focus
 
 - `exercises/01.cpp`: print user-provided integers in reverse order.

languages/cpp/01-foundations/strings/README.md

@@ -38,6 +38,12 @@ g++ -std=c++17 -Wall -Wextra -pedantic example/string-clean-and-tokenize.cpp -o
 - Using string indexes without boundary checks.
 - Not checking for `std::string::npos` after `find`.
 
+## Cross-Language Notes
+
+- Compared with C++, the other tracks usually hide more of the low-level string-management cost while keeping the same parsing goals.
+- Relative to Python and TypeScript, C# and Go keep more explicit API choices around splitting, trimming, and rebuilding text.
+- The main comparison is text-processing convenience versus how visible allocation and mutation remain.
+
 ## Exercise Focus
 
 - `exercises/01.cpp`: count words in a sentence.

languages/cpp/02-core/algorithms-basics/README.md

@@ -34,6 +34,12 @@ g++ -std=c++17 -Wall -Wextra -pedantic example/main.cpp -o algorithms_basics_exa
 - Initializing min/max incorrectly.
 - Running multiple passes when one pass is enough.
 
+## Cross-Language Notes
+
+- Compared with the C++ baseline, the same traversal and aggregation ideas are expressed with different defaults for loops, collections, and helper functions.
+- Relative to Python, the statically typed tracks make intermediate state and accumulator types more explicit.
+- The useful comparison is algorithm shape staying constant while the surrounding syntax and safety rails change.
+
 ## Exercise Focus
 
 - `exercises/01.cpp`: linear search and first index.

languages/cpp/02-core/sorting-and-searching/README.md

@@ -38,6 +38,12 @@ g++ -std=c++17 -Wall -Wextra -pedantic example/stable-vs-unstable-sort.cpp -o so
 - Off-by-one index errors.
 - Forgetting to return `-1` when target is missing.
 
+## Cross-Language Notes
+
+- Compared with C++, the other tracks keep the same ordering and lookup ideas but differ in how visible comparator design is.
+- Relative to Python and TypeScript, Go and C# ask for more explicit decisions around helper functions and ordering rules.
+- The key comparison is not the algorithm itself, but how much control each language exposes around sorting behavior.
+
 ## Exercise Focus
 
 - `exercises/01.cpp`: implement selection sort.

languages/cpp/03-advanced/templates-basics/README.md

@@ -38,6 +38,12 @@ g++ -std=c++17 -Wall -Wextra -pedantic example/generic-print-and-sum.cpp -o temp
 - Assuming all types support required operators.
 - Confusing template type deduction behavior.
 
+## Cross-Language Notes
+
+- Compared with C++, this concept broadens from templates into each language's own reusable generic abstraction model.
+- Relative to Go and C#, TypeScript generics stay expressive without runtime specialization, while Python treats the same idea more informally.
+- The useful comparison is how each language generalizes logic without abandoning type clarity.
+
 ## Exercise Focus
 
 - `exercises/01.cpp`: template swap function.

languages/csharp/01-foundations/arrays-and-vectors/README.md

@@ -28,6 +28,12 @@ dotnet run --project example/arrays-and-vectors-example.csproj
 - Off-by-one errors while reading N elements.
 - Not handling empty input in frequency tasks.
 
+## Cross-Language Notes
+
+- Compared with the C++ version, each track solves the same sequence problems with a different default dynamic-array model.
+- The key comparison is where bounds safety, resizing behavior, and iteration ergonomics come from in each language.
+- This module is most useful when you notice how similar tasks feel different under `vector`, `List<T>`, slices, Python lists, and TypeScript arrays.
+
 ## Exercise Focus
 
 - exercises/01.cs: read N integers, store them, and print them in reverse order.

languages/csharp/01-foundations/strings/README.md

@@ -28,6 +28,12 @@ dotnet run --project example/strings-example.csproj
 - Comparing palindromes before removing punctuation and case differences.
 - Failing to handle inputs without alphabetic characters.
 
+## Cross-Language Notes
+
+- Compared with C++, the other tracks usually hide more of the low-level string-management cost while keeping the same parsing goals.
+- Relative to Python and TypeScript, C# and Go keep more explicit API choices around splitting, trimming, and rebuilding text.
+- The main comparison is text-processing convenience versus how visible allocation and mutation remain.
+
 ## Exercise Focus
 
 - exercises/01.cs: count words in an input line using robust whitespace handling.

languages/csharp/02-core/algorithms-basics/README.md

@@ -28,6 +28,12 @@ dotnet run --project example/algorithms-basics-example.csproj
 - Using incorrect initial values for min/max.
 - Repeating loops when a single pass can compute all metrics.
 
+## Cross-Language Notes
+
+- Compared with the C++ baseline, the same traversal and aggregation ideas are expressed with different defaults for loops, collections, and helper functions.
+- Relative to Python, the statically typed tracks make intermediate state and accumulator types more explicit.
+- The useful comparison is algorithm shape staying constant while the surrounding syntax and safety rails change.
+
 ## Exercise Focus
 
 - exercises/01.cs: linear search and first index.

languages/csharp/02-core/sorting-and-searching/README.md

@@ -28,6 +28,12 @@ dotnet run --project example/sorting-and-searching-example.csproj
 - Off-by-one errors in `left` and `right` boundaries.
 - Forgetting to return `-1` when a target is missing.
 
+## Cross-Language Notes
+
+- Compared with C++, the other tracks keep the same ordering and lookup ideas but differ in how visible comparator design is.
+- Relative to Python and TypeScript, Go and C# ask for more explicit decisions around helper functions and ordering rules.
+- The key comparison is not the algorithm itself, but how much control each language exposes around sorting behavior.
+
 ## Exercise Focus
 
 - exercises/01.cs: implement selection sort.

languages/csharp/03-advanced/templates-basics/README.md

@@ -28,6 +28,12 @@ dotnet run --project example/templates-basics-example.csproj
 - Using `object` instead of generics and losing type safety.
 - Hiding constraints until compile errors become confusing.
 
+## Cross-Language Notes
+
+- Compared with C++, this concept broadens from templates into each language's own reusable generic abstraction model.
+- Relative to Go and C#, TypeScript generics stay expressive without runtime specialization, while Python treats the same idea more informally.
+- The useful comparison is how each language generalizes logic without abandoning type clarity.
+
 ## Exercise Focus
 
 - exercises/01.cs: generic swap function.