POJ3614 Sunscreen 贪心

先按照minSPF排序，然后每次选择最大可以选的就可以了。

注意反向map的lower还是upper

/* ***********************************************
Author        :BPM136
Created Time  :2018/7/15 17:05:21
File Name     :3614.cpp
************************************************ */

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<vector>
#include<map>
using namespace std;

typedef long long ll;
typedef map<int,int, greater<int > > MIIG;

const int N = 100005;

int n,m;

struct cow {
    int mn,mx;
}a[N];
bool cmp_a(cow a,cow b) {
    if(a.mn==b.mn) return a.mx<b.mx;
    return a.mn>b.mn;
}

int main() {
    MIIG M;
    M.clear();

    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++) scanf("%d%d",&a[i].mn,&a[i].mx);
    for(int i=1;i<=m;i++) {
        int v,nm;
        scanf("%d%d",&v,&nm);
        M[v]+=nm;
    }
    sort(a+1,a+n+1,cmp_a);
    int ans=0;
    for(int i=1;i<=n;i++) {
        MIIG::iterator t=M.lower_bound(a[i].mx);
        if(t==M.end() || t->first<a[i].mn) continue;
        t->second--;
        ans++;
        if(t->second==0) M.erase(t);
    }
    cout<<ans<<endl;
    return 0;
}