[树形DP FWT] HDU 5909 Tree Cutting

给一个带点权的树 文有多少个连通子图的异或和为0~m-1
没什么好说吧 水题

#include
#include
#include
using namespace std;
typedef long long ll;

inline char nc(){
  static char buf[100000],*p1=buf,*p2=buf;
  return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline void read(int &x){
  char c=nc(),b=1;
  for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
  for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}

const int P=1e9+7;
const int INV2=(P+1)>>1;

inline void FWT(int n,int *a,int r){
  for (int i=1;i1)
    for (int j=0;j1))
      for (int k=0;kint x=a[j+k],y=a[j+k+i];
    if (r) a[j+k]=(x+y)%P,a[j+k+i]=(x+P-y)%P;
    else a[j+k]=(ll)(x+y)*INV2%P,a[j+k+i]=(ll)(x+P-y)*INV2%P;
      }
}

const int N=1105;

struct edge{
  int u,v,next;
}G[N<<1];
int head[N],inum;
inline void add(int u,int v,int p){
  G[p].u=u; G[p].v=v; G[p].next=head[u]; head[u]=p;
}
#define V G[p].v

int n,m;
int f[N][N],g[N];
int val[N];

inline void dfs(int u,int fa){
  for (int p=head[u];p;p=G[p].next)
    if (V!=fa)
      dfs(V,u);
  for (int i=0;i<m;i++) g[i]=0; g[0]++;
  for (int p=head[u];p;p=G[p].next)
    if (V!=fa){
      FWT(m,g,1); FWT(m,f[V],1);
      for (int i=0;i<m;i++) g[i]=(ll)g[i]*f[V][i]%P;
      FWT(m,g,0); FWT(m,f[V],0);
    }
  f[u][0]++;
  for (int i=0;i<m;i++) (f[u][i^val[u]]+=g[i])%=P;
}

int main(){
  int T,iu,iv;
  freopen("t.in","r",stdin);
  freopen("t.out","w",stdout);
  read(T);
  while (T--){
    read(n); read(m);
    for (int i=1;i<=n;i++) head[i]=0; inum=0;
    for (int i=1;i<=n;i++) for (int j=0;j<m;j++) f[i][j]=0;
    for (int i=1;i<=n;i++) read(val[i]);
    for (int i=1;iread(iu),read(iv),add(iu,iv,++inum),add(iv,iu,++inum);
    dfs(1,0);
    for (int i=0;i<m;i++) g[i]=0;
    for (int i=1;i<=n;i++) for (int j=0;j<m;j++) (g[j]+=f[i][j])%=P;
    g[0]-=n;
    for (int i=0;i<m;i++) printf("%d%c",g[i],i==m-1?'\n':' ');
  }
  return 0;
}