51nod1773 A国的贸易

51nod1773

http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1773

#include<cstdio>
#include<map>
#define gc getchar()
const int mod=1e9+7,inv2=(mod+1)>>1;
int a[1<<21],b[1<<21];
int n,m;
inline int fwt(int *a,int d,int f){
	int x,y;
	for(register int i=1;i<d;i<<=1)
		for(register int j=0;j<d;j+=(i<<1))
			for(register int k=j;k<i+j;++k){
				x=a[k];y=a[i+k];a[k]=(x+y)%mod;a[i+k]=(x-y+mod)%mod;
				if(f==-1)a[k]=1ll*a[k]*inv2%mod,a[i+k]=1ll*a[i+k]*inv2%mod;
			}
}
inline int fp(int a,int b){
	int res=1;
	while(b){
		if(b&1)res=1ll*res*a%mod;
		a=1ll*a*a%mod;b>>=1;
	}
	return res;
}
inline int read(){
	char c;while(c=gc,c==' '||c=='
');int data=c-48;
	while(c=gc,c>='0'&&c<='9')data=c-48+(data<<1)+(data<<3);return data;
}
int wr[51];
inline void write(int x){
	if(!x){
		puts("0");
		return;
	}
	while(x)wr[++wr[0]]=x%10,x/=10;
	while(wr[0])putchar(48+wr[wr[0]--]);
	putchar(' ');
}
int main(){
	n=read();m=read();
	for(register int i=0;i<(1<<n);++i)a[i]=read();
	b[0]=1;for(register int i=0;i<n;++i)b[1<<i]=1;
	fwt(a,(1<<n),1),fwt(b,(1<<n),1);
	for(register int i=0;i<(1<<n);++i)a[i]=1ll*a[i]*fp(b[i],m)%mod;
	fwt(a,(1<<n),-1);
	for(register int i=0;i<(1<<n);++i)write(a[i]);
	return 0;
}

　　

fwt板子

inline void FWT(int *a,int n){  
    for(register int d=1;d<n;d<<=1)
		for(register int m=d<<1,i=0;i<n;i+=m)  
            for(register int j=0;j<d;++j){  
                int x=a[i+j],y=a[i+j+d];
                //xor:a[i+j]=x+y,a[i+j+d]=x-y;  
                //and:a[i+j]=x+y;  
                //or:a[i+j+d]=x+y;  
            }  
}  
inline void UFWT(int *a,int n){  
    for(register int d=1;d<n;d<<=1)  
        for(register int m=d<<1,i=0;i<n;i+=m)  
            for(register int j=0;j<d;++j){  
                int x=a[i+j],y=a[i+j+d]; 
                //xor:a[i+j]=(x+y)/2,a[i+j+d]=(x-y)/2;  
                //and:a[i+j]=x-y;  
                //or:a[i+j+d]=y-x;  
            }  
}  
inline void solve(int *a,int *b,int n){  
    FWT(a,n);FWT(b,n);  
    for(register int i=0;i<n;++i) a[i]=1LL*a[i]*b[i];  
    UFWT(a,n);  
}