bzoj1029: [JSOI2007]建筑抢修

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define rep(i,s,t) for(int i=s;i<=t;i++)
#define dwn(i,s,t) for(int i=s;i>=t;i--)
#define clr(x,c) memset(x,c,sizeof(x))
#define ll long long
ll read(){
    ll x=0,f=1;char c=getchar();
    while(!isdigit(c)){
        if(c==‘-‘) f=-1;c=getchar();
    }
    while(isdigit(c)) x=x*10+c-‘0‘,c=getchar();
    return x;
} 
const int nmax=150005;
struct node{
    ll c,t;
    bool operator<(const node&rhs)const{
      return t<rhs.t;}
};
node ns[nmax];
priority_queue<ll>q;
int main(){
    ll n=read();
    rep(i,1,n) ns[i].c=read(),ns[i].t=read();
    sort(ns+1,ns+n+1);
    //rep(i,1,n) printf("%lld %lld\n",ns[i].c,ns[i].t);
    ll cur=ns[1].c;q.push(ns[1].c);int ans=1;
    rep(i,2,n){
        if(cur+ns[i].c<=ns[i].t){
            cur+=ns[i].c;q.push(ns[i].c);ans++;
            continue;
        }
        ll tmp=q.top();
        if(tmp>ns[i].c&&cur-tmp+ns[i].c<=ns[i].t){
            cur=cur-tmp+ns[i].c;q.pop();q.push(ns[i].c);
        }
    }
    printf("%d\n",ans);
    return 0;
}