Cost Flow wording bipartite graph maximum weight matching note

Today is mainly found time to write a maximum weight matching is not necessarily the maximum matching, so give points for each side of a s directly connected to the side t, expressed this point can not match.

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn=1500005;
inline int read(){
	char c=getchar();int t=0,f=1;
	while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
	while(isdigit(c)){t=(t<<3)+(t<<1)+(c^48);c=getchar();}
	return t*f;
}
struct edge{
	int v,p,w,c;
}e[maxn<<1];
int h[2005],cnt=1;
inline void add(int a,int b,int c,int d){
	e[++cnt].p=h[a];
	e[cnt].v=b;
	e[cnt].w=c;
	e[cnt].c=d;
	h[a]=cnt;
}
int n,m,k,s,t;
const int inf=1e18;
int vis[2005],dis[2005],inq[2005];
int bfs(){
	queue<int> q;
	while(!q.empty())q.pop();
	for(int i=1;i<=t;i++){dis[i]=inf;inq[i]=0;}
	dis[s]=0;
	while(!q.empty())q.pop();
	q.push(s);
	while(!q.empty()){
		int u=q.front();q.pop();inq[u]=0;
		for(int i=h[u];i;i=e[i].p){
			int v=e[i].v;
			//printf("%lld %lld %lld\n",v,dis[v],dis[u]+e[i].c);
			if(dis[v]>dis[u]+e[i].c&&e[i].w){
				dis[v]=dis[u]+e[i].c;
				if(!inq[v]){
					q.push(v);
					inq[v]=1;
				}
			}
		}
	}
	return dis[t]!=inf;
}
int ht[2005],cost;
int dfs(int u,int rest){
	if((u==t)||rest==0)return rest;
	vis[u]=1;
	int tot=0;
	for(int &i=ht[u];i;i=e[i].p){
		int v=e[i].v;
		if(dis[v]==dis[u]+e[i].c&&e[i].w&&((!vis[v])||(v==t))){
			int di=dfs(v,min(rest,e[i].w));
			rest-=di;tot+=di;
			e[i].w-=di;e[i^1].w+=di;cost+=di*e[i].c; 
			if(rest==0)break;
		}
	}
	return tot;
}
void dinic(){
	while(bfs()){
		vis[t]=1;
		while(vis[t]){
			for(int i=1;i<=t;i++){vis[i]=0;ht[i]=h[i];}
			int tmp=dfs(s,inf);
		//	printf("%lld\n",tmp);
		}
	}
}
void print(int x){
	if(x==0){puts("0");return ;}
	char s[55];
	memset(s,0,sizeof(s));
	int cnt=0;
	while(x){
		s[++cnt]=x%10+'0';x/=10;
	}
	for(int i=cnt;i>=1;i--)printf("%c",s[i]);
	puts("");
}
signed main(){
	//freopen("6.in","r",stdin);
	//freopen("6.out","w",stdout);
	n=read(),m=read();k=read();
	for(int i=1;i<=k;i++){
		int a=read(),b=read(),c=-read();	
		add(a,b+n,1,c);
		add(b+n,a,0,-c);
	}
	s=n+m+1,t=n+m+2;
	for(int i=1;i<=n;i++){
		add(s,i,1,0);add(i,s,0,0);
		add(i,t,1,0);add(t,i,0,0);
	}
	for(int i=1;i<=m;i++){
		add(i+n,t,1,0);add(t,i+n,0,0);
	}
	dinic();
	cost=cost*-1;
	print(cost);
	return 0;
}