bzoj4332[JSOI2012]分零食

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
const int maxn=1024*32*4;
#define double long double
const double pi=acos(-1);
struct comp{
  double x,y;
  comp(){}
  comp(double a,double b){x=a;y=b;}
  comp operator +(const comp &a){return comp(x+a.x,y+a.y);}
  comp operator -(const comp &a){return comp(x-a.x,y-a.y);}
  comp operator *(const comp &a){return comp(x*a.x-y*a.y,x*a.y+y*a.x);}
} ;//a:存储原始多项式 b:存储原始多项式的卷积 c:存储答案 d:存储原多项式的n/2次方
int mod;
int a[maxn],c[maxn],d[maxn],e[maxn];
void fft(comp* a,int n,int sign){
  for(int i=1,j=0,k=n;i<n;++i,k=n){
    do j^=(k>>=1);while(j<k);if(i<j)swap(a[i],a[j]);
  }
  for(int j=2;j<=n;j<<=1){
    int m=j>>1;comp wn(cos(pi*2/j),sign*sin(pi*2/j));
    for(comp *p=a;p!=a+n;p=p+j){
      comp w(1,0);
      for(int k=0;k<m;++k,w=w*wn){
    comp t=p[m+k]*w;p[m+k]=p[k]-t;p[k]=p[k]+t;
      }
    }
  }
  if(sign==-1){
    for(int i=0;i<n;++i)a[i].x/=n;
  }
}
int N=1;int m;
int mo(double x){
  return (((int)floor(x+0.5))%mod+mod)%mod;
}
void mult(int *a,int *b,int *res){
  static comp tmp1[maxn],tmp2[maxn];
  for(int i=0;i<N;++i)tmp1[i]=comp(a[i],0),tmp2[i]=comp(b[i],0);
  fft(tmp1,N,1);fft(tmp2,N,1);
  for(int i=0;i<N;++i)tmp1[i]=tmp1[i]*tmp2[i];
  fft(tmp1,N,-1);
  for(int i=0;i<N;++i)res[i]=mo(tmp1[i].x);
}
void qsum(int n){
  if(n==1){
    for(int i=0;i<N;++i)c[i]=a[i];
    for(int i=0;i<N;++i)d[i]=a[i];
  }else{
    qsum(n>>1);
    mult(c,d,e);
//for(int i=0;i<N;++i)
      //e[i]=c[i]*d[i]+c[i];
    for(int i=0;i<N;++i)c[i]=mo(c[i]+e[i]);
    memset(c+(N>>1),0,sizeof(comp)*(N>>1));
    if(n&1){
      mult(c,a,e);
      for(int i=0;i<N;++i)c[i]=mo(a[i]+e[i]);
      memset(c+(N>>1),0,sizeof(comp)*(N>>1));
    }

    mult(d,d,d);
    memset(d+(N>>1),0,sizeof(comp)*(N>>1));

    if(n&1){
      mult(d,a,d);
      memset(d+(N>>1),0,sizeof(comp)*(N>>1));
    }

  }
}
int main(){
  scanf("%d%d",&m,&mod);
  int n,o,s,u;scanf("%d%d%d%d",&n,&o,&s,&u);
  n=min(n,m);
  for(int i=1;i<=m;++i){
    int t=i%mod;
    a[i]=(o*t*t+s*t+u)%mod;
  }
  while(N<=m)N<<=1;N<<=1;
  qsum(n);printf("%d\n",c[m]);
  return 0;
}