C++11(clang++ 3.9) 解法, 执行用时: 88ms, 内存消耗: 22364K, 提交时间: 2018-08-13 20:55:53

#include<bits/stdc++.h>
#define maxn 1000010
#define ll long long
using namespace std;

struct pnt{
	int x,y;
}ps[maxn],s,t;
struct trt{
	int u,v,c;
}ts[maxn];
int n,m;
ll tag[2][maxn];
const ll INF=1LL<<60;
void read(int &x){
	char ch=x=0;
	bool fl=false;
	while(!isdigit(ch))
		fl|=ch=='-',ch=getchar();
	while(isdigit(ch))
		x=x*10+ch-'0',ch=getchar();
	x=fl?-x:x;
}
ll crs(pnt a,pnt b,pnt std){
	return 1LL*(a.x-std.x)*(b.y-std.y)-1LL*(a.y-std.y)*(b.x-std.x);
}
bool out(pnt tmp){
	for(int i=1;i<=n;i++){
		pnt a=ps[i],b=ps[i%n+1];
		if(crs(tmp,b,a)>0)
			return true;
	}
	return false;
}
void solve(pnt tmp,int tp){
	memset(tag[tp],0,sizeof(tag[tp]));
	for(int i=1;i<=m;i++){
		int u=ts[i].u,v=ts[i].v,c=ts[i].c;
		if(crs(ps[v],tmp,ps[u])>0)
			tag[tp][u]+=c,tag[tp][v]-=c;
		else
			tag[tp][v]+=c,tag[tp][1]+=c,tag[tp][u]-=c;
	}
	for(int i=2;i<=n;i++)
		tag[tp][i]+=tag[tp][i-1];
}
int main(){
	read(n),read(m);
	for(int i=1;i<=n;i++)
		read(ps[i].x),read(ps[i].y);
	for(int i=1;i<=m;i++){
		read(ts[i].u),read(ts[i].v),read(ts[i].c);
		if(ts[i].u>ts[i].v)
			swap(ts[i].u,ts[i].v);
	}
	read(s.x),read(s.y),read(t.x),read(t.y);
	solve(s,0),solve(t,1);
	if(out(s)&&out(t))
		puts("0");
	else if(out(s)){
		ll anst=INF;
		for(int i=1;i<=n;i++)
			anst=min(anst,tag[1][i]);
		printf("%lld\n",anst);
	}
	else if(out(t)){
		ll anss=INF;
		for(int i=1;i<=n;i++)
			anss=min(anss,tag[0][i]);
		printf("%lld\n",anss);
	}
	else{
		ll ans=0,anss=INF,anst=INF;
		for(int i=1;i<=m;i++){
			if((crs(ps[ts[i].v],s,ps[ts[i].u])>0)^(crs(ps[ts[i].v],t,ps[ts[i].u])>0))
				ans+=ts[i].c;
		}
		for(int i=1;i<=n;i++)
			anss=min(anss,tag[0][i]),anst=min(anst,tag[1][i]);
		printf("%lld\n",min(ans,anss+anst));
	}
	return 0;
}