Update Copyright

README.md

@@ -65,3 +65,10 @@ We provide three processed datasets: Kwai, Tiktok, and Movielnes.
    Validation file. Each line is a user with her/his 1,000 negative and several positive interactions with items: (userID and micro-video ID)  
 -`test.npy`
    Test file. Each line is a user with her/his 1,000 negative and several positive interactions with items: (userID and micro-video ID)  
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+Copyright (C) <year>  Shandong University
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+This program is licensed under the GNU General Public License 3.0 (https://www.gnu.org/licenses/gpl-3.0.html). Any derivative work obtained under this license must be licensed under the GNU General Public License as published by the Free Software Foundation, either Version 3 of the License, or (at your option) any later version, if this derivative work is distributed to a third party.
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+The copyright for the program is owned by Shandong University. For commercial projects that require the ability to distribute the code of this program as part of a program that cannot be distributed under the GNU General Public License, please contact <[email protected]> to purchase a commercial license.