luogu2869 [USACO07DEC]美食的食草动物Gourmet Grazers

先满足挑剔的

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstdio>
using namespace std;
typedef long long ll;
int n, m, tmp, rot, cnt;
ll ans;
struct Cow{
	int pri, gre;
}cow[100005];
struct Gra{
	int pri, gre;
}gra[100005];
struct Treap{
	int val[100005], hav[100005], l[100005], r[100005], rnd[100005];
	void lRotate(int &k){
		int t=r[k]; r[k] = l[t]; l[t] = k; k = t;
	}
	void rRotate(int &k){
		int t=l[k]; l[k] = r[t]; r[t] = k; k = t;
	}
	void insert(int &k, int x){
		if(!k){
			k = ++cnt; hav[k] = 1;
			val[k] = x; rnd[k] = rand();
			return ;
		}
		if(val[k]==x)	hav[k]++;
		else if(val[k]<x){
			insert(r[k], x);
			if(rnd[r[k]]<rnd[k])	lRotate(k);
		}
		else{
			insert(l[k], x);
			if(rnd[l[k]]<rnd[k])	rRotate(k);
		}
	}
	void queryNxt(int k, int x){
		if(!k)	return ;
		if(val[k]>=x)	tmp = val[k], queryNxt(l[k], x);
		else	queryNxt(r[k], x);
	}
	void del(int &k, int x){
		if(!k)	return ;
		if(val[k]==x){
			if(hav[k]>1){
				hav[k]--;
				return ;
			}
			if(l[k]*r[k]==0)	k = l[k] + r[k];
			else if(rnd[l[k]]<rnd[r[k]])
				rRotate(k), del(k, x);
			else
				lRotate(k), del(k, x);
		}
		else if(val[k]<x)	del(r[k], x);
		else	del(l[k], x);
	}
}treap;
bool cmp1(Cow x, Cow y){
	return x.gre>y.gre;
}
bool cmp2(Gra x, Gra y){
	return x.gre>y.gre;
}
int main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++)
		scanf("%d %d", &cow[i].pri, &cow[i].gre);
	for(int i=1; i<=m; i++)
		scanf("%d %d", &gra[i].pri, &gra[i].gre);
	sort(cow+1, cow+1+n, cmp1);
	sort(gra+1, gra+1+m, cmp2);
	int j=1;
	for(int i=1; i<=n; i++){
		tmp = -1;
		while(j<=m && gra[j].gre>=cow[i].gre){
			treap.insert(rot, gra[j].pri);
			j++;
		}
		treap.queryNxt(rot, cow[i].pri);
		if(tmp==-1){
			cout<<"-1"<<endl;
			return 0;
		}
		ans += tmp;
		treap.del(rot, tmp);
	}
	cout<<ans<<endl;
	return 0;
}