Test chấm thử:
- UOCSO: http://coder.chuyenluongthevinh.edu.vn/Problem/Details/5774
- MAX_SORT: http://coder.chuyenluongthevinh.edu.vn/Problem/Details/5775
- HOTEN: http://coder.chuyenluongthevinh.edu.vn/Problem/Details/5776
Hướng dẫn giải: https://hsgtindongnai.blogspot.com/2017/12/huong-giai-e-thi-hoc-sinh-gioi-lop-9.html
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