The above code is a product of my final dissertation in the undergraduate programme of the Physics Department of NKUA. It is an Order Statistic Tree based of a Red Black Tree with proper augmentations, in C. The operations supported are FIND_NODE, INSERT_NODE, DELETE_NODE, SELECT_NODE, RANK_NODE, PRINT_TREE and PRINT_2D_TREE. I hope it helps your endeavors in Computer Science.