[CQOI2012] 交换棋子 （费用流）

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#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<climits>
#include<queue>
using namespace std;
inline int read(){
    int f=,ans=;char c=getchar();
    while(c<''||c>''){if(c=='-')f=-;c=getchar();}
    while(c>=''&&c<=''){ans=ans*+c-'';c=getchar();}
    return f*ans;
}
queue<int> que;
const int MAXN=;
const int N=;
struct node{
    int u,v,cost,w,nex;
}x[MAXN<<];
int head[MAXN],S,T,cnt,dis[MAXN],vis[MAXN],cost,INF=INT_MAX;
void add(int u,int v,int cost,int w){
//    printf("u:%d v:%d cost:%d w:%d\n",u,v,cost,w);
    x[cnt].u=u,x[cnt].v=v,x[cnt].cost=cost,x[cnt].w=w,x[cnt].nex=head[u],head[u]=cnt++;swap(u,v),w=,cost=-cost;
    x[cnt].u=u,x[cnt].v=v,x[cnt].cost=cost,x[cnt].w=w,x[cnt].nex=head[u],head[u]=cnt++;
}
bool spfa(){
    memset(dis,/,sizeof(dis)),memset(vis,,sizeof(vis));
    int inf=dis[];dis[S]=,vis[S]=,que.push(S);
    while(!que.empty()){
        int xx=que.front();que.pop();
        for(int i=head[xx];i!=-;i=x[i].nex){
            if(x[i].w&&dis[x[i].v]>dis[xx]+x[i].cost){
                dis[x[i].v]=dis[xx]+x[i].cost;
                if(!vis[x[i].v]) vis[x[i].v]=,que.push(x[i].v);
            }
        }vis[xx]=;
    }return dis[T]!=inf;
}
int dfs(int u,int flow){
//    printf("u:%d flow:%d\n",u,flow);
    if(u==T) return flow;
    int used=;vis[u]=;
    for(int i=head[u];i!=-;i=x[i].nex){
        if(x[i].w&&dis[x[i].v]==dis[u]+x[i].cost&&!vis[x[i].v]){
            int slow=dfs(x[i].v,min(flow-used,x[i].w));used+=slow;
            x[i].w-=slow,x[i^].w+=slow;
            cost+=slow*x[i].cost;
            if(used==flow) break;
        }
    }if(!used) dis[u]=-;
    vis[u]=;
    return used;
}
int dinic(){
    int ans=;cost=;
    while(spfa()){memset(vis,,sizeof(vis)),ans+=dfs(S,INF);}
    return ans;
}
char A[N][N],B[N][N],lim[N][N];
int n,m,sum;
int dx[]={,,,-,-,-,,};
int dy[]={,,-,,,-,,-};
int Q(int x,int y){return (x-)*m+y;}
int main(){
//    freopen("8.in","r",stdin);
    memset(head,-,sizeof(head));
    n=read(),m=read();S=,T=n*m*+;
    for(int i=;i<=n;i++) scanf("%s",A[i]+);
    for(int i=;i<=n;i++) scanf("%s",B[i]+);
    for(int i=;i<=n;i++) scanf("%s",lim[i]+);
    for(int i=;i<=n;i++)
        for(int j=;j<=m;j++){
            if(A[i][j]==B[i][j]&&A[i][j]==) continue;
            A[i][j]-='',B[i][j]-='',lim[i][j]-='';
            if(A[i][j]==B[i][j]){

                    add(Q(i,j),Q(i,j)+n*m,,lim[i][j]/);
                    add(Q(i,j)+*n*m,Q(i,j),,lim[i][j]);

                continue;
            }
            if(A[i][j]==){
                sum++;
                add(S,Q(i,j),,);
                add(Q(i,j),Q(i,j)+n*m,,(lim[i][j]+)/);
                add(Q(i,j)+*n*m,Q(i,j),,(lim[i][j]-)/);
                continue;
            }
            if(B[i][j]==){
                add(Q(i,j),Q(i,j)+n*m,,(lim[i][j]-)/);
                add(Q(i,j)+*n*m,Q(i,j),,(lim[i][j]+)/);
                add(Q(i,j),T,,);
            }
        }
    for(int i=;i<=n;i++){
        for(int j=;j<=m;j++){
            for(int k=;k<;k++){
                int bx=i+dx[k],by=j+dy[k];
                if(bx>=&&bx<=n&&by>=&&by<=m){
                    add(Q(i,j)+n*m,Q(bx,by)+*n*m,,INF);
                }
            }
        }
    }
    int Ans=dinic();
    if(Ans!=sum){printf("-1");return ;}
    printf("%d\n",cost);
}/*
1 2
1 0
0 1
1 1
*/