bzoj1029: [JSOI2007]建筑抢修

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

struct node
{
    int t,ed;
}a[210000];
bool cmp(node n1,node n2){return n1.ed<n2.ed;}
multiset<int> s;
int main()
{
    int n;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)scanf("%d%d",&a[i].t,&a[i].ed);
    sort(a+1,a+n+1,cmp);
    
    int now=0,ans=0;
    for(int i=1;i<=n;i++)
    {
        if(a[i].t+now<=a[i].ed)
        {
            now+=a[i].t;
            ans++;
            s.insert(a[i].t);
        }
        else
        {
            int q=*--s.end();
            if(a[i].t<q)
            {
                int sum=s.count(q);
                s.erase(q);
                for(int j=1;j<sum;j++)s.insert(q);
                s.insert(a[i].t);
                now+=a[i].t-q;
            }
        }
    }
    printf("%d\n",ans);
    return 0;
}