bzoj1029题解

 1 #pragma GCC optimize(2)
 2 #include <algorithm>
 3 #include <cstdio>
 4 #include <functional>
 5 #include <set>
 6 #define REP(i,low,high) for(register int i=(low);i<=(high);i++)
 7 using namespace std;
 8 struct node
 9 {
10     int ft,et;
11     node() {}
12     int input() {return scanf("%d%d",&ft,&et);}
13     bool operator<(const node &another)const{return et<another.et;}
14 }a[150010];
15 int n;
16 multiset<int, greater<int> > sav;
17 int main()
18 {
19     scanf("%d",&n),sav.clear(); REP(i,1,n) a[i].input(); sort(a+1,a+n+1);
20     int ans=0,now=0;
21     REP(i,1,n)
22     {
23         if(a[i].ft+now<=a[i].et) sav.insert(a[i].ft),ans++,now+=a[i].ft;
24         else
25         {
26             multiset<int>::iterator tp=sav.begin();
27             if(*tp>a[i].ft) now+=a[i].ft-*tp,sav.erase(tp),sav.insert(a[i].ft);
28         }
29     }
30     return printf("%d\n",ans),0;
31 }