http://acm.hdu.edu.cn/showproblem.php?pid=4280

模板题裸的最大流，n和m较大，时间卡的紧，要用堆栈加bfs优化

#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;

const int maxn=100000+10;
const int inf=0x3f3f3f3f;
int n,m;
struct point{
    int x,y;
}p[maxn];
struct Edge{
    int to,next,cap,flow;
}edge[maxn<<1];
int to1;
int head[maxn],gap[maxn],dep[maxn],cur[maxn];
void init(){
    to1=0;
    memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w,int rw=0){
    edge[to1].to=v;
    edge[to1].cap=w;
    edge[to1].next=head[u];
    edge[to1].flow=0;
    head[u]=to1++;
    edge[to1].to=u;
    edge[to1].cap=rw;
    edge[to1].next=head[v];
    edge[to1].flow=0;
    head[v]=to1++;
}
int Q[maxn];
void bfs(int s,int t){
    memset(dep,-1,sizeof(dep));
    memset(gap,0,sizeof(gap));
    gap[0]=1;
    int front=0,rear=0;
    dep[t]=0;
    Q[rear++]=t;
    while(front!=rear){
        int u=Q[front++];
        for(int i=head[u];i!=-1;i=edge[i].next){
            int v=edge[i].to;
            if(dep[v]!=-1)continue;
            Q[rear++]=v;
            dep[v]=dep[u]+1;
            gap[dep[v]]++;
        }
    }
}
int S[maxn];
int sap(int s,int t,int N){
    bfs(s,t);
    memcpy(cur,head,sizeof(head));
    int top=0;
    int u=s;
    int ans=0;
    while(dep[s]<N){
        if(u==t){
            int Min=inf;
            int inser;
            for(int i=0;i<top;i++){
                if(Min>edge[S[i]].cap-edge[S[i]].flow){
                    Min=edge[S[i]].cap-edge[S[i]].flow;
                    inser=i;
                }
            }
            for(int i=0;i<top;i++){
                edge[S[i]].flow+=Min;
                edge[S[i]^1].flow-=Min;
            }
            ans+=Min;
            top=inser;
            u=edge[S[top]^1].to;
            continue;
        }
        bool flag=false;
        int v;
        for(int i=cur[u];i!=-1;i=edge[i].next){
            v=edge[i].to;
            if(edge[i].cap-edge[i].flow&&dep[v]+1==dep[u]){
                flag=true;
                cur[u]=i;
                break;
            }
        }
        if(flag){
            S[top++]=cur[u];
            u=v;
            continue;
        }
        int Min=N;
        for(int i=head[u];i!=-1;i=edge[i].next){
            if(edge[i].cap-edge[i].flow&&dep[edge[i].to]<Min){
                Min=dep[edge[i].to];
                cur[u]=i;
            }
        }
        gap[dep[u]]--;
        if(!gap[dep[u]])return ans;
        dep[u]=Min+1;
        gap[dep[u]]++;
        if(u!=s)u=edge[S[--top]^1].to;
    }
    return ans;
}

int main(){
    int T;
    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&n,&m);
        init();
        int left=100001,right=-100001,l,r;
        for(int i=0;i<n;i++){
            scanf("%d%d",&p[i].x,&p[i].y);
            if(left>p[i].x){
                left=p[i].x;l=i;
            }
            if(right<p[i].x){
                right=p[i].x;r=i;
            }
        }
        for(int i=0;i<m;i++){
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            u--,v--;
            addedge(u,v,w,w);
        }
        int s=l,t=r;
        int ans=sap(s,t,n);
        printf("%d\n",ans);
    }
    return 0;
}