洛谷 - P2278 - 操作系统 - 模拟

https://www.luogu.org/problemnew/show/P2278

题目没有说同时到达的优先级最大的应该处理谁。

讲道理就是处理优先级最大的。

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

struct Process {
    int id;
    int itime;
    int dtime;
    int pri;

    inline bool operator<(const Process& p)const {
        if(pri==p.pri)
            //大根堆，大的先出，符号反向
            return itime>p.itime;
        else
            return pri<p.pri;
    }

    inline bool pri_less_than(const Process &p) {
        return pri<p.pri;
    }

    inline void input(int &i,int &it,int &dt,int &p) {
        id=i;
        itime=it;
        dtime=dt;
        pri=p;
    }

} p,cur;

priority_queue<Process> pq;
ll curtime,deltatime,pretime,nexttime;

void show_state() {
    printf("ptime=%lld  ctime=%lld  dtime=%lld\n",pretime,curtime,deltatime);
    printf(" curid=%d  curdtime=%d\n",cur.id,cur.dtime);
    printf(" pq.size=%d\n",(int)pq.size());
    printf("\n");
}

void change_process() {
    if(pq.empty())
        return;
    if(cur.id==0) {
        //puts("next process!");
        cur=pq.top();
        pq.pop();
        nexttime=curtime+cur.dtime;
        //show_state();
    } else if(cur.pri_less_than(pq.top())) {
        //puts("change process!");
        //命令保存当前进程并取出新进程，更新时间
        pq.push(cur);
        cur=pq.top();
        pq.pop();
        nexttime=curtime+cur.dtime;
        //show_state();
    }
}

void do_process() {
    //puts("do process!");
    if(cur.id==0)
        return;
    //show_state();
    ll mintime=min(deltatime,(ll)cur.dtime);
    deltatime-=mintime;
    pretime+=mintime;
    cur.dtime-=mintime;
    if(cur.dtime==0) {
        printf("%d %lld\n",cur.id,pretime);
        cur.id=0;
        nexttime=-1;
    }
    //show_state();
}

void update() {
    do {
        do_process();
        //当前进程做不完了，堆顶是不是有比它大的？
        change_process();
    } while(cur.id&&deltatime);
    //CPU正忙，尽可能从堆里面取出进程

}

int main() {
#ifdef Yinku
    freopen("Yinku.in","r",stdin);
#endif // Yinku
    int id,itime,dtime,pri;
    scanf("%d%d%d%d",&id,&itime,&dtime,&pri);

    curtime=itime;
    pretime=itime;
    deltatime=curtime-pretime;

    p.input(id,itime,dtime,pri);
    pq.push(p);
    update();

    while(~scanf("%d%d%d%d",&id,&itime,&dtime,&pri)) {
        while(cur.id&&itime>nexttime) {
            //puts("!");
            pretime=curtime;
            curtime=nexttime;
            deltatime=curtime-pretime;
            update();
        }

        //puts("?");
        if(cur.id==0)
            pretime=itime;
        else
            pretime=curtime;
        curtime=itime;
        deltatime=curtime-pretime;
        p.input(id,itime,dtime,pri);
        pq.push(p);
        update();
    }

    pretime=curtime;
    curtime=1e18;
    deltatime=curtime-pretime;
    update();

    return 0;
}