fix(solutions): fix: more memory issues thanks to -fsanitize=address flag with gcc

challenges/heap-algorithm/README.md

@@ -6,6 +6,8 @@ Created by [@theoludwig](https://github.com/theoludwig) on 8 November 2021.
 
 Write a program that generates all possible unique permutations of a string.
 
+The order of the generated permutations is important, see the example below.
+
 ## Source
 
 - [Heap's Algorithm - Wikipedia](https://en.wikipedia.org/wiki/Heap%27s_algorithm)
@@ -25,10 +27,10 @@ abc
 ```txt
 abc
 bac
-cba
-bca
 cab
 acb
+bca
+cba
 ```
 
 See the `test` folder for examples of input/output.