Starry

脑子一直在降智 #include <bits/stdc++.h> /* #include<ext/pb_ds/assoc_container.hpp> #include<ext/pb_ds/hash_policy.hpp> */ using namespace std; const double eps = 1e-10; const double pi = 3.1415926535897932384626433832795; const double eln 

求 区间有多少

转换为二维数点

警钟长鸣！提交 #include <bits/stdc++.h> /* #include<ext/pb_ds/assoc_container.hpp> #include<ext/pb_ds/hash_policy.hpp> */ using namespace std; const double eps = 1e-10; const double pi = 3.1415926535897932384626433832795; const double eln 

考虑每个点可以成为好节点的情况数，对于该节点，指定一个计数方向。 #include <bits/stdc++.h> /* #include<ext/pb_ds/assoc_container.hpp> #include<ext/pb_ds/hash_policy.hpp> */ using namespace std; const double eps = 1e-10; const double pi = 3.14159265358979323846264338327

#include <bits/stdc++.h> /* #include<ext/pb_ds/assoc_container.hpp> #include<ext/pb_ds/hash_policy.hpp> */ using namespace std; const double eps = 1e-10; const double pi = 3.1415926535897932384626433832795; const double eln = 2.718