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摘要: https://codeforces.com/problemset/problem/1288/C Examples input 2 2 output 5 input 10 1 output 55 input 723 9 output 157557417 Note In the first test 阅读全文
posted @ 2020-08-29 21:37 RioTian 阅读(336) 评论(1) 推荐(0)