ccsu_deer

参考博客：博客1 博客2 先贴模板 #include<bits/stdc++.h> using namespace std; typedef long long ll; #define IO ios::sync_with_stdio(false) #define pb push_back #define mk make_pair const int N = 1e5+10; const int mod = 1e9+7; ll a, b; const long long S=20; l.