[CSU1911]Card Game

题目传送门：Vjudge，CSU-ACM

题目大意：

给定两个有n个数的数组\(A,B\)，每次询问给定一个数，回答在每个数组里选一个数\(x\)，或起来结果为\(x\)的方案数

FWT板子题，直接套就好（然后我居然把\(A_i\)++打成\(A_i\)=1了……）

/*program from Wolfycz*/
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define inf 0x7f7f7f7f
using namespace std;
typedef long long ll;
typedef unsigned int ui;
typedef unsigned long long ull;
inline char gc(){
    static char buf[1000000],*p1=buf,*p2=buf;
    return p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++;
}
inline int frd(){
    int x=0,f=1; char ch=gc();
    for (;ch<'0'||ch>'9';ch=gc())   if (ch=='-')    f=-1;
    for (;ch>='0'&&ch<='9';ch=gc()) x=(x<<3)+(x<<1)+ch-'0';
    return x*f;
}
inline int read(){
    int x=0,f=1; char ch=getchar();
    for (;ch<'0'||ch>'9';ch=getchar())  if (ch=='-')    f=-1;
    for (;ch>='0'&&ch<='9';ch=getchar())    x=(x<<3)+(x<<1)+ch-'0';
    return x*f;
}
inline void print(int x){
    if (x<0)    putchar('-'),x=-x;
    if (x>9)    print(x/10);
    putchar(x%10+'0');
}
int mlt(int a,int b){
    int res=1;
    for (;b;b>>=1,a=a*a)    if (b&1)    res=res*a;
    return res;
}
void FWT(ll *a,int n,int flag){
    for (int i=2;i<=n;i<<=1)
        for (int j=0;j<n;j+=i)
            for (int k=0;k<i>>1;k++)
                a[(i>>1)+j+k]+=a[j+k]*flag;
}
ll A[(1<<19)+10],B[(1<<19)+10],C[(1<<19)+10];
int n,m,Q;
int main(){
    char s[30];
    for (int T=read(),Case=0;T;T--){
        printf("Case #%d:\n",++Case);
        memset(A,0,sizeof(A));
        memset(B,0,sizeof(B));
        scanf("%d%d",&n,&m); m=1<<m;
        for (int i=1;i<=n;i++){
            scanf("%s",s);
            int l=strlen(s),x=0;
            for (int j=0;j<l;j++)   x=(x<<1)+s[j]-'0';
            A[x]++;
        }
        for (int i=1;i<=n;i++){
            scanf("%s",s);
            int l=strlen(s),x=0;
            for (int j=0;j<l;j++)   x=(x<<1)+s[j]-'0';
            B[x]++;
        }
        FWT(A,m,1),FWT(B,m,1);
        for (int i=0;i<m;i++)   C[i]=A[i]*B[i];
        FWT(C,m,-1);
        scanf("%d",&Q);
        for (int i=1;i<=Q;i++){
            scanf("%s",s);
            int l=strlen(s),x=0;
            for (int j=0;j<l;j++)   x=(x<<1)+s[j]-'0';
            printf("%lld\n",C[x]);
        }
    }
    return 0;
}

[CSU1911]Card Game

原文：https://www.cnblogs.com/Wolfycz/p/10436278.html