BZOJ2706 : [SDOI2012]棋盘覆盖

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
char sn[200010],sm[200010],type[5];int K;
namespace SubA{
const int N=105,M=N*N,inf=~0U>>2;
int n,m,cnt,i,j,a[N][N],id[N][N],S,T,h[M],gap[M],ans;
struct E{int t,f;E*nxt,*pair;}*g[M],*d[M],pool[M*6],*cur=pool;
inline void add(int s,int t){
  if(!s||!t)return;
  E*p=cur++;p->t=t;p->f=1;p->nxt=g[s];g[s]=p;
  p=cur++;p->t=s;p->f=0;p->nxt=g[t];g[t]=p;
  g[s]->pair=g[t];g[t]->pair=g[s];
}
int sap(int v,int flow){
  if(v==T)return flow;
  int rec=0;
  for(E*p=d[v];p;p=p->nxt)if(h[v]==h[p->t]+1&&p->f){
    int ret=sap(p->t,min(flow-rec,p->f));
    p->f-=ret;p->pair->f+=ret;d[v]=p;
    if((rec+=ret)==flow)return flow;
  }
  if(!(--gap[h[v]]))h[S]=T;
  gap[++h[v]]++;d[v]=g[v];
  return rec;
}
void solve(){
  sscanf(sn,"%d",&n);
  sscanf(sm,"%d",&m);
  while(K--)scanf("%d%d",&i,&j),a[i][j]=1;
  for(i=1;i<=n;i++)for(j=1;j<=m;j++)if(!a[i][j])id[i][j]=++cnt;
  S=cnt+1;T=S+1;
  for(i=1;i<=n;i++)for(j=1;j<=m;j++)if((i+j)&1)add(S,id[i][j]);else add(id[i][j],T);
  for(i=1;i<=n;i++)for(j=1;j<=m;j++)if((i+j)&1){
    add(id[i][j],id[i][j-1]);
    add(id[i][j],id[i][j+1]);
    add(id[i][j],id[i-1][j]);
    add(id[i][j],id[i+1][j]);
  }
  for(gap[0]=T,i=1;i<=T;i++)d[i]=g[i];
  while(h[S]<T)ans+=sap(S,inf);
  printf("%d",ans);
}
}
namespace SubB{
const int N=262150;
const double pi=acos(-1.0);
struct comp{
  double r,i;comp(double _r=0,double _i=0){r=_r,i=_i;}
  comp operator+(const comp&x){return comp(r+x.r,i+x.i);}
  comp operator-(const comp&x){return comp(r-x.r,i-x.i);}
  comp operator*(const comp&x){return comp(r*x.r-i*x.i,r*x.i+i*x.r);}
  comp conj(){return comp(r,-i);}
}A[N],B[N];
int n,i,j,k,pos[N],c[N];
void FFT(comp*a,int n,int t){
  for(int i=1;i<n;i++)if(i<pos[i])swap(a[i],a[pos[i]]);
  for(int d=0;(1<<d)<n;d++){
    int m=1<<d,m2=m<<1;double o=pi*2/m2*t;comp _w(cos(o),sin(o));
    for(int i=0;i<n;i+=m2){
      comp w(1,0);
      for(int j=0;j<m;j++){
        comp&A=a[i+j+m],&B=a[i+j],t=w*A;
        A=B-t;B=B+t;w=w*_w;
      }
    }
  }
  if(t==-1)for(int i=0;i<n;i++)a[i].r/=n;
}
void solve(){
  n=strlen(sn);
  for(i=0;i<n;i++)A[i]=comp(sn[n-i-1]-‘0‘,sn[n-i-1]-‘0‘);
  for(k=1;k<n+n;k<<=1);
  j=__builtin_ctz(k)-1;
  for(i=0;i<k;i++)pos[i]=pos[i>>1]>>1|((i&1)<<j);
  FFT(A,k,1);
  for(i=0;i<k;i++){
    j=(k-i)&(k-1);
    B[i]=(A[i]*A[i]-(A[j]*A[j]).conj())*comp(0,-0.25);
  }
  FFT(B,k,-1);
  for(i=0;i<k;i++)c[i]=int(B[i].r+0.5);
  for(i=0;i<k;i++)c[i+1]+=c[i]/10,c[i]%=10;
  for(n=k;!c[n];n--);
  c[0]--;
  for(i=n;~i;i--){
    if(i)c[i-1]+=c[i]%3*10;
    c[i]/=3;
  }
  while(n&&!c[n])n--;
  for(i=n;~i;i--)printf("%d",c[i]);
}
}
namespace SubC{
const int N=11,M=180000;
int n,m,i,j,k,t,S,x,E,a[N][N],cnt,q[M],h[1<<22],f[M][2],g[M][2],ans;
inline int get(int x,int y){return x>>(y+y)&3;}
inline void clr(){for(int i=1;i<=cnt;i++)f[i][0]=f[i][1]=-1;}
inline void nxt(){for(int i=1;i<=cnt;i++)g[i][0]=f[i][0],g[i][1]=f[i][1];}
inline void up(int&x,int y){if(x<y)x=y;}
void solve(){
  sscanf(sn,"%d",&n);
  sscanf(sm,"%d",&m);
  while(K--)scanf("%d%d",&i,&j),a[i-1][j-1]=1;
  for(S=0;S<(1<<(m+m));S++){
    for(j=1,i=0;i<m;i++)if(get(S,i)==3){j=0;break;}
    if(j)q[++cnt]=S,h[S]=cnt;
  }
  clr();
  nxt();
  for(S=i=0;i<m;i++)S|=1<<(i+i);
  g[h[S]][0]=0;
  for(i=0;i<n;i++)for(j=0;j<m;j++){
    clr();
    for(k=1;k<=cnt;k++)for(t=0;t<2;t++)if(~g[k][t]){
      S=q[k],x=get(S,j),E=S^(x<<(j+j));
      if(x==2){
        if(a[i][j])continue;
        up(f[h[E^(1<<(j+j))]][x>0],g[k][t]);
      }else{
        up(f[h[E]][x>0],g[k][t]);
        if(a[i][j])continue;
        if(i>0)if(!x&&!a[i-1][j])up(f[h[E^(2<<(j+j))]][1],g[k][t]+1);
        if(j>=2)if(!get(S,j-1)&&!a[i][j-1]&&!get(S,j-2)&&!a[i][j-2]){
          up(f[h[E^(1<<(j+j-4)^(1<<(j+j-2)^(1<<(j+j))))]][x>0],g[k][t]+1);
        }
        if(j>=1)if(!get(S,j-1)&&!a[i][j-1]){
          up(f[h[E^(2<<(j+j-2))^(1<<(j+j))]][x>0],g[k][t]+1);
          up(f[h[E^(1<<(j+j-2))^(2<<(j+j))]][x>0],g[k][t]+1);
          if(i>0){
            if(!t&&!a[i-1][j-1]){
              up(f[h[E^(1<<(j+j-2))^(1<<(j+j))]][x>0],g[k][t]+1);
            }
            if(!x&&!a[i-1][j]){
              up(f[h[E^(1<<(j+j-2))^(1<<(j+j))]][1],g[k][t]+1);
            }
          }
        }
      }
    }
    nxt();
  }
  for(k=1;k<=cnt;k++){
    S=q[k];
    for(j=1,i=0;i<m;i++)if(get(S,i)==2){j=0;break;}
    if(j)for(t=0;t<2;t++)up(ans,g[k][t]);
  }
  printf("%d",ans);
}
}
int main(){
  scanf("%s%s%d%s",sm,sn,&K,type);
  if(type[0]==‘A‘)SubA::solve();
  if(type[0]==‘B‘)SubB::solve();
  if(type[0]==‘C‘)SubC::solve();
  return 0;
}