手写 bitset 模板

#include<vector>
using namespace std;
typedef unsigned long long ull;
struct Bitset{size_t siz=0;vector<ull> x;inline void init(size_t SIZ){siz=SIZ;x.resize((SIZ>>6)+((SIZ&63)?1:0));}inline void set(const size_t &a){x[a>>6]|=1ull<<(a&63);}inline void set(){x.assign(x.size(),1);}inline void reset(const size_t &a){x[a>>6]&=~(1ull<<(a&63));}inline void reset(){x.assign(x.size(),0);}inline void flip(const size_t &a){x[a>>6]^=1ull<<(a&63);}inline bool ask(const size_t &a)const{return x[a>>6]>>(a&63)&1;}inline Bitset &operator^=(const Bitset &a){for(size_t i=0;i<x.size();i++) x[i]^=a.x[i];return *this;}inline Bitset split(const size_t &l,const size_t &r)const{Bitset res;size_t len=r-l+1;res.init(len);size_t block=l>>6,bit=l&63;for(size_t i=0;i<res.x.size();i++){res.x[i]=(x[i+block]>>bit);if(bit&&i+block+1<x.size()) res.x[i]|=x[i+block+1]<<(64-bit);}if(len&63) res.x.back()&=(1ull<<(len&63))-1;return res;}inline Bitset operator^(const Bitset &x)const{return Bitset(*this)^=x;}
};