Uva 1153 Keep the Customer Satisfied (贪心+优先队列)

struct cp
{
    bool operator () (node a,node b)
    {
        //可以理解为我如何让后入队的优先出队
        if(b.need>a.need) return true;
        else return false;
    }
};

#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#include <algorithm>

using namespace std;
const int maxn=800005;
struct node
{
    int need,ed;
}data[maxn];

struct cp
{
    bool operator () (node a,node b)
    {
        if(b.need>a.need) return true;
        else return false;
    }
};

bool cmp(node a,node b)
{
    if(a.ed<b.ed) return true;
    else if(a.ed==b.ed)
    {
        if(a.need<b.need) return true;
        else return false;
    }
    else return false;
}

int main()
{
    int n;
    int t;
    cin>>t;
    while(t--)
    {
        cin>>n;
        for(int i=0;i<n;i++)
        {
            cin>>data[i].need>>data[i].ed;
        }
        sort(data,data+n,cmp);
        priority_queue<node,vector<node>,cp> q;
        int tmp=0,ans=0;
        for(int i=0;i<n;i++)
        {
            q.push(data[i]);
            tmp=tmp+data[i].need;
            if(tmp>data[i].ed)
            {
                node k=q.top();
                q.pop();
                tmp=tmp-k.need;
                ans--;
            }
            ans++;
        }
        if(ans<=0) ans=0;
        cout<<ans<<endl;
        if(t) cout<<endl;
    }
    return 0;
}