hi,
can not tell about exercises but if you are looking for implementation code then please visit:
sanfoundry.com/cpp-programming-examples-data-structures/[
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bogotobogo.com/Algorithms/algorithms.php[
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These might not be the 'BEST' but the provided code generally works.
Plus you can try variations on your own. Also there are too many types of trees and graphs. So you will have to search more for their specific implementations.
The code of 'boost' library is a great demo of how data structures can be implemented but its some what difficult to understand for beginners.
heres what i did :: for the explanation and exercises i followed a book :
Data Structures using C++ by DS Malik[
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hope this helps !!