HDU 3377 Plan

/*第一种方法*/
#include<queue>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int mn=977147;
int i;
struct na{
    int x,z;
    na(int xx,int zz):x(xx),z(zz){}
};
int n,m,x,y,z,a[21],k,en,u=0,p1,p2;
bool map[21][21];
int f[2][mn+1],ans;
int v[2][mn+1];
int re[21][21];
queue <na> q;
inline int gx(int x,int q1,int q2){k=0;for (register int i=m+1;i;i--) k=k*3+(i==x?q1:(i==x+1?q2:a[i]));return k;}
inline void up(int x,int z,int lj,bool la){
    if (la) lj+=re[x/m+1][x%m+1];
    x++;
    k=x%2;
    if (v[k][z]!=x) v[k][z]=x,f[k][z]=-1e9,q.push(na(x,z));
    f[k][z]=max(f[k][z],lj);
}
int main(){
    //freopen("a.in","r",stdin);
    register int i,j;
    while(scanf("%d%d",&n,&m)!=EOF){
        u++;
        printf("Case %d: ",u);
        ans=-1e9;
        memset(map,0,sizeof(map));memset(v,0,sizeof(v));memset(re,0,sizeof(re));memset(f,0,sizeof(f));
        for (i=1;i<=m;i++)
        for (j=1;j<=n;j++)
        map[i][j+2]=1;
        for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
        scanf("%d",&re[i+2][j]);
        n+=4;
        m+=2;
        en=n*m-1;
        for (i=1;i<=m;i++) map[i][1]=map[i][n]=1;
        for (i=1;i<=n;i++) map[m][i]=1;
        map[1][2]=1;map[m-2][n-1]=1;
        if (n==1&&m==1){
            printf("%d\n",re[1][1]);
            continue;
        }
        f[0][0]=0;v[0][0]=1;
        q.push(na(0,0));
        while(!q.empty()){
            na no=q.front();q.pop();
            int an=f[no.x%2][no.z];
            if(no.x%m==0) no.z*=3;
            x=no.x%m+1;y=no.x/m+1;
            for (i=1;i<=m+1;i++) a[i]=0;
            for (i=1,j=no.z;j;i++,j/=3) a[i]=j%3;
            if (!map[x][y])up(no.x,gx(x,0,0),an,0);else
            if (a[x]==1&&a[x+1]==2){
                if (no.x==en) ans=max(ans,an);
            }else if (a[x]==2&&a[x+1]==1) up(no.x,gx(x,0,0),an,1);else
                if (a[x]==0&&a[x+1]==0){
                if (no.x!=en&&no.x!=1) up(no.x,gx(x,0,0),an,0);
                if (map[x][y+1]&&map[x+1][y]) up(no.x,gx(x,1,2),an,1);
            }else if (a[x]==0){
                if (map[x+1][y]) up(no.x,gx(x,0,a[x+1]),an,1);
                if (map[x][y+1]) up(no.x,gx(x,a[x+1],0),an,1);
            }else if (a[x+1]==0){
                if (map[x+1][y]) up(no.x,gx(x,0,a[x]),an,1);
                if (map[x][y+1]) up(no.x,gx(x,a[x],0),an,1);
            }else if (a[x]==a[x+1]){
                p1=p2=0;
                if (a[x]==1)
                for (j=0,i=x+2;i<=m;i++){
                    if (a[i]==1) j--;
                    if (a[i]==2) j++;
                    if (j>0&&!p1) p1=i,j--;
                    if (j>0&&p1){p2=i;break;}
                }else
                for (j=0,i=x-1;i;i--){
                    if (a[i]==1) j++;
                    if (a[i]==2) j--;
                    if (j>0&&!p2) p2=i,j--;
                    if (j>0&&p2){p1=i;break;}
                }
                a[p1]=1;a[p2]=2;up(no.x,gx(x,0,0),an,1);
            }
        }
        printf("%d\n",ans);
    }
}

/*第二种方法*/
#include<queue>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int i;
struct na{
    int x,z;
    na(int xx,int zz):x(xx),z(zz){}
};
int n,m,x,y,z,a[21],k,en,u=0,p1,p2;
bool map[21][21];
int f[2][1277148],ans;
int v[2][1277148];
int re[21][21];
queue <na> q;
inline int gx(int x,int q1,int q2){k=0;for (register int i=m+1;i;i--) k=k*3+(i==x?q1:(i==x+1?q2:a[i]));return k;}
inline void up(int x,int z,int lj,bool la){
    if (la) lj+=re[x/m+1][x%m+1];
    x++;
    k=x%2;
    if (v[k][z]!=x) v[k][z]=x,f[k][z]=lj,q.push(na(x,z));
    if (lj>f[k][z]) f[k][z]=lj;
}
int main(){
    register int i,j;
    while(scanf("%d%d",&n,&m)!=EOF){
        u++;
        ans=0;
        memset(map,0,sizeof(map));memset(v,0,sizeof(v));memset(f,0,sizeof(f));
        en=n*m-1;
        for (i=1;i<=m;i++)
        for (j=1;j<=n;j++)
        map[i][j]=1;
        for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
        scanf("%d",&re[i][j]);
        if (n==1&&m==1){
            printf("Case %d: %d\n",u,re[1][1]);
            continue;
        }
        f[0][1]=0;
        v[0][0]=1;
        q.push(na(0,1));
        while(!q.empty()){
            na no=q.front();q.pop();
            int an=f[no.x%2][no.z];
            if (no.x%m==0) no.z*=3;
            x=no.x%m+1;y=no.x/m+1;
            for (i=1;i<=m+1;i++) a[i]=0;
            for (i=1,j=no.z;j;i++,j/=3) a[i]=j%3;
            if (no.x==en){
                k=0;
                for (i=1;i<=m+1;i++) k+=a[i]!=0;
                if (k==1&&(a[m]==1||a[m+1]==1)&&an+re[n][m]>ans) ans=an+re[n][m];
                continue;
            }
            if (a[x]==2&&a[x+1]==1){
                up(no.x,gx(x,0,0),an,1);
            }else if (a[x]==0&&a[x+1]==0){
                up(no.x,gx(x,0,0),an,0);
                if (map[x][y+1]&&map[x+1][y])
                up(no.x,gx(x,1,2),an,1);
            }else if (a[x]==0){
                if (map[x+1][y]) up(no.x,gx(x,0,a[x+1]),an,1);
                if (map[x][y+1]) up(no.x,gx(x,a[x+1],0),an,1);
            }else if (a[x+1]==0){
                if (map[x+1][y]) up(no.x,gx(x,0,a[x]),an,1);
                if (map[x][y+1]) up(no.x,gx(x,a[x],0),an,1);
            }else if (a[x]==1&&a[x+1]==1){
                p1=p2=0;
                for (j=0,i=x+2;i<=m+1;i++){
                    if (a[i]==1) j--;
                    if (a[i]==2) j++;
                    if (j>0&&!p1) p1=i,j--;
                    if (j>0&&p1){p2=i;break;}
                }
                a[p1]=1;a[p2]=2;
                up(no.x,gx(x,0,0),an,1);
            }else if (a[x]==2&&a[x+1]==2){
                p1=p2=0;
                for (j=0,i=x-1;i;i--){
                    if (a[i]==1) j++;
                    if (a[i]==2) j--;
                        if (j>0&&!p2) p2=i,j--;
                    if (j>0&&p2){p1=i;break;}
                }
                a[p1]=1;a[p2]=2;up(no.x,gx(x,0,0),an,1);
            }
        }
        printf("Case %d: %d\n",u,ans);
    }
}