网络流求助

#include<bits/stdc++.h>
using namespace std;
const int N=2e6+6;
#define ll long long
#define inf 2147483647
struct Edge{
	int to,nxt;
	ll value;
}edges[N];
int n,m,s,t;
int tmp,head[N];
int cnt=1;
void add(int u,int v,int w){
	edges[++cnt]={v,head[u],w};
	head[u]=cnt;
}
void addedge(int u,int v,int w){
	add(u,v,w);
	add(v,u,w);
}
int dep[N],cur[N];
bool bfs(){
	for(int i=2;i<=n;i++){
		dep[i]=inf;
	}
	queue<int>Q;
	Q.push(s);
	memcpy(cur,head,sizeof cur);
	dep[s]=1;
	while(!Q.empty()){
		int u=Q.front(); Q.pop();
		for(int i=head[u];i;i=edges[i].nxt){
			int v=edges[i].to;
			if(dep[v]>dep[u]+1&&edges[i].value){
				dep[v]=dep[u]+1;
				Q.push(v);
			}
		}
	}
return dep[t]!=inf;
}
ll max_flow;
ll dfs(int u,ll flow){
//	cout<<u<<"\n";
	if(u==t){
		max_flow+=flow;
		return flow;
	}
	ll used=0;
	for(int i=cur[u];i;i=edges[i].nxt){
		cur[u]=i;
		int v=edges[i].to;
		if(dep[v]==dep[u]+1&&edges[i].value){
			ll rflow=dfs(v,min(edges[i].value,flow-used));
			if(rflow){
				used+=rflow;
				edges[i].value-=rflow;
				edges[i^1].value+=rflow;
				if(flow==used){
					return used;
				}
			}
		}
	}
return used;
}
ll dinic(){
	while(bfs()){
		dfs(s,inf);
	}
return max_flow;
}
int main(){
	cin.tie(0)->sync_with_stdio(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		for(int j=1;j<m;j++){
			cin>>tmp;
			addedge((i-1)*m+j,(i-1)*m+j+1,tmp);
		}
	}
	for(int i=1;i<n;i++){
		for(int j=1;j<=m;j++){
			cin>>tmp;
			addedge((i-1)*m+j,(i-1)*m+j+m,tmp);
		}
	}
	for(int i=1;i<n;i++){
		for(int j=1;j<m;j++){
			cin>>tmp;
			addedge((i-1)*m+j,(i-1)*m+j+m+1,tmp);
		}
	}
	s=1,t=n*m;
	cout<<dinic();
return 0;
}