我直接用的Dinic算法,开始用vector存图（sb了），成功 Memory_Limit_Exceed，后来改用数组存图就过了。
#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
#include<cstring>
using namespace std;typedef long long ll;
const int maxn=1000000+1000;
const ll INF=1e18;struct Edge{int to,next;long long cap;
}edge[maxn*6];
int iter[maxn],level[maxn];
int head[maxn],edgenum;
int n,m;
void Add(int from,int to,long long cap){edge[edgenum].to=to;edge[edgenum].cap=cap;edge[edgenum].next=head[from];head[from]=edgenum++; edge[edgenum].to=from;edge[edgenum].cap=cap;edge[edgenum].next=head[to];head[to]=edgenum++;
}void bfs(int s){memset(level,-1,sizeof(level));queue<int>que;level[s]=0;que.push(s);while(!que.empty()){int v=que.front();que.pop();for(int i=head[v];i!=-1;i=edge[i].next){Edge e=edge[i];if(e.cap>0&&level[e.to]<0){level[e.to]=level[v]+1;que.push(e.to);}} }
}long long dfs(int v,int t,long long f){if(v==t) return f;if(iter[v]==0) iter[v]=head[v];for(int &i=iter[v];i!=-1;i=edge[i].next){Edge &e=edge[i];if(e.cap>0&&level[e.to]>level[v]){long long d=dfs(e.to,t,min(e.cap,f));if(d>0){e.cap-=d;edge[i^1].cap+=d;return d;}}}return 0;
} long long max_flow(int s,int t){long long flow=0;for(;;){bfs(s);if(level[t]<0) return flow;memset(iter,0,sizeof(iter));long long f;while((f=dfs(s,t,INF))>0) flow+=f;}
}int main(){scanf("%d%d",&n,&m);int tot;memset(head,-1,sizeof(head));edgenum=0;for(int i=0;i<n;i++){tot=0;for(int j=0;j<m-1;j++){long long cap;scanf("%lld",&cap);Add(i*m+tot,i*m+tot+1,cap);tot++;}}for(int i=0;i<n-1;i++){for(int j=0;j<m;j++){long long cap;scanf("%lld",&cap);Add(i*m+j,(i+1)*m+j,cap);}}for(int i=0;i<n-1;i++){int tot=0;for(int j=0;j<m-1;j++){long long cap;scanf("%lld",&cap);Add(i*m+tot,(i+1)*m+tot+1,cap);tot++;}}printf("%lld\n",max_flow(0,m*n-1));
}