modifying headings for tree traversal chapter
modifying headings for tree traversal chapter

leios/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,leios/algorithm-archive,Gathros/algorithm-archive,leios/algorithm-archive