BZOJ

# data range

$n\le 10^9,m\le 5\times 10^4$

# solution

$\%$了一发$yyb$的代码才知道原来可以快速幂的时候可以不用每次$FWT$

orz 神仙yyb

# Code

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<iomanip>
#include<cstring>
#include<complex>
#include<vector>
#include<cstdio>
#include<string>
#include<bitset>
#include<ctime>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<set>
#define Cpy(x,y) memcpy(x,y,sizeof(x))
#define Set(x,y) memset(x,y,sizeof(x))
#define FILE "a"
#define mp make_pair
#define pb push_back
#define RG register
#define il inline
using namespace std;
typedef unsigned long long ull;
typedef vector<int>VI;
typedef long long ll;
typedef double dd;
const int N=1<<16;
const int M=1e5+10;
const int mod=1e9+7;
const int base=26;
const dd eps=1e-6;
const int inf=2147483647;
const ll INF=1ll<<60;
const ll P=100000;
RG ll data=0,w=1;RG char ch=getchar();
while(ch!='-'&&(ch<'0'||ch>'9'))ch=getchar();
if(ch=='-')w=-1,ch=getchar();
while(ch<='9'&&ch>='0')data=data*10+ch-48,ch=getchar();
return data*w;
}

il void file(){
srand(time(NULL)+rand());
freopen(FILE".in","r",stdin);
freopen(FILE".out","w",stdout);
}

int pri[N];bool vis[N];
il void upd(int &a,int b){a+=b;if(a>=mod)a-=mod;}
il void dec(int &a,int b){if(b)upd(a,mod-b);}
il void sieve(){
vis[1]=1;
for(RG int i=2;i<N;i++){
if(!vis[i])pri[++pri[0]]=i;
for(RG int j=1;j<=pri[0]&&1ll*i*pri[j]<N;j++){
vis[i*pri[j]]=1;if(i%pri[j]==0)break;
}
}
}
il void FWT_xor(int *a,int n,int opt){
for(RG int i=1,x,y,inv2=(mod+1)/2;i<n;i<<=1)
for(RG int j=0,p=i<<1;j<n;j+=p)
for(RG int k=0;k<i;k++){
x=a[j+k];y=a[i+j+k];a[i+j+k]=x;
upd(a[j+k],y);dec(a[i+j+k],y);
if(opt==-1)a[j+k]=1ll*a[j+k]*inv2%mod,a[i+j+k]=1ll*a[i+j+k]*inv2%mod;
}
}
int f[N],g[N];

int main()
{
sieve();RG int n,m;
while(scanf("%d%d",&n,&m)!=EOF){
memset(f,0,sizeof(f));memset(g,0,sizeof(g));f[0]=1;
for(RG int i=1;pri[i]<=m&&i<=pri[0];i++)g[pri[i]]=1;
FWT_xor(f,N,1);FWT_xor(g,N,1);
while(n){
if(n&1)for(RG int i=0;i<N;i++)f[i]=1ll*f[i]*g[i]%mod;
for(RG int i=0;i<N;i++)g[i]=1ll*g[i]*g[i]%mod;
n>>=1;
}
FWT_xor(f,N,-1);
printf("%d\n",f[0]);
}
return 0;
}


posted @ 2018-10-01 22:12  cjfdf  阅读(160)  评论(0编辑  收藏