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单开还行，做了7个很ok了个人感觉。C题贪心题目还是三个人一起贪不容易错的。一个人贪心要想清楚方向和正确性，wa*4。
F题大胆！H题是个不错的题，倒着维护一下组合数，使用二项式定理即可；
但是H一开始想错了，急着写了个线段树上去，结果用不到，大概浪费了1h吧，所以先想清楚再落笔更好！
这场dirt不多，就C题。