UVA12298--FFT(递归)

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<complex>
using namespace std;
typedef long double lf;
const int maxn=1000005;
const lf pi=acos(-1);
complex<lf>a[maxn],b[maxn],c[maxn],d[maxn],ans[maxn];
bool isprime[maxn];
void init(){
memset(isprime,1,sizeof(isprime));
for(int i=2;i<=50000;i++)
if(isprime[i]&&((lf)i*i<=50000))
for(int j=i*i;j<=50000;j+=i)
isprime[j]=0;
}
void fft(complex<lf>*y,int n,int flag){
if(n==1)return;
complex<lf>y0[n>>1],y1[n>>1];
for(int i=0;i<n;i+=2){
y0[i>>1]=y[i];
y1[i>>1]=y[i+1];
}fft(y0,n>>1,flag),fft(y1,n>>1,flag);
complex<lf>tmp(cos(2*pi/n),flag*sin(2*pi/n)),x(1,0);
for(int i=0;i<(n>>1);i++,x*=tmp){
y[i]=y0[i]+x*y1[i];
y[i+(n>>1)]=y0[i]-x*y1[i];
}
}
int main(){
int A,B,C;
init();
while(scanf("%d%d%d",&A,&B,&C)&&(A+B+C)){
int n=1,k;
char ch[10];
while(n<=4*B)n<<=1;
for(int i=0;i<=B;i++)
a[i]=b[i]=c[i]=d[i]=(isprime[i]?0:1);
for(int i=B+1;i<=n;i++)
a[i]=b[i]=c[i]=d[i]=0;
while(C--){
scanf("%d%s",&k,ch);
switch(ch[0]){
case 'S':a[k]=0;break;
case 'H':b[k]=0;break;
case 'C':c[k]=0;break;
case 'D':d[k]=0;break;
}
}
fft(a,n,1),fft(b,n,1);
fft(c,n,1),fft(d,n,1);
for(int i=0;i<n;i++)
ans[i]=a[i]*b[i]*c[i]*d[i];
fft(ans,n,-1);
for(int i=A;i<=B;i++)
printf("%lld\n",(long long)(ans[i].real()/n+0.5));
}
return 0;
}