040000 tree 449ec8ebb915c6fa56635b864ffd9689e278c0ce	alg.merge
040000 tree d64de48af129f0d39a57f1a38060bfb5542f9f83	alg.modifying.operations
040000 tree fdf650d656cb1fc3a7e3f47ed30e21046da9dca6	alg.nonmodifying
040000 tree 50a2b8301276eaf854adec2687b5327724ff758c	alg.sorting