PAT 1017. Queueing at Bank

又是排队模拟

#include <iostream>

#include <cstdlib>

#include <vector>

#include <list>

#include <queue>



using namespace std;



class Man {

public:

    int arrive;

    int need;

    int start;

    Man(int a, int n) : arrive(a), need(n), start(0) {}

};



class ArriveCmp {

public:

    vector<Man>& customers;

    ArriveCmp(vector<Man>& mans) : customers(mans) {}

    bool operator() (int i, int j) {

        return customers[i].arrive < customers[j].arrive;

    }

};



int max(int a, int b) {

    return a>b? a : b;

}



int fetch_customer(list<int>& wait, vector<Man>& customers, int elapsed_time) {

    if (wait.size() <= 0) {

        return -1;

    }

    int c = wait.front();

    customers[c].start = max(elapsed_time, customers[c].arrive);

    wait.pop_front();

    return c;

}



void print_time(int time) {

    int s = time % 60;

    int m = time/60 % 60;

    int h = time / 3600;

    printf("%02d:%02d:%02d\n", h, m, s);

}



int main() {



    int N, W;

    

    scanf("%d%d", &N, &W);

    

    vector<Man> customers;

    vector<int> windows(W, -1);

    list<int> wait;

    ArriveCmp cmp(customers);

    

    int idx = 0;

    for (int i=0; i<N; i++) {

        int h, m, s, need;

        scanf("%d:%d:%d%d", &h, &m, &s, &need);

        if (h >= 17 && (m || s)) {

            // customers arrived too late

            continue;

        }

        need = need * 60; // convert minute to second

        if (need > 3600) {

            // no customer can occupy one window for more than 1hour.

            need = 3600;

        }

        

        customers.push_back(Man(h * 3600 + m * 60 + s, need));

        wait.push_back(idx++);

    }



    wait.sort(cmp);

    

    int elapsed_time = 8 * 3600;

    

    // <finish_time, customer_index>

    priority_queue<pair<int, int> , vector<pair<int, int> >, greater<pair<int, int> > > work;

    

    int next = -1;

    

    while (!wait.empty()) {

        if (!work.empty()) {

            int fast = work.top().second;

            Man& c = customers[fast];

            elapsed_time = c.start + c.need;

            work.pop();

        }

        while (work.size() < W) {

            next = fetch_customer(wait, customers, elapsed_time);

            if (next == -1) {

                break;

            }

            Man& c = customers[next];

            work.push(make_pair(c.start + c.need, next));

        }

    }

    

    int n = customers.size();

    int alltime = 0;

    for (int i=0; i<n; i++) {

        alltime += customers[i].start - customers[i].arrive;

    }

    

    printf("%.1f", alltime * 1.0 / 60 / n );

    

    system("pause");

    return 0;

}

写的有点烦啊