CCF201909-4 推荐系统（100分）模拟

Posted 2021-09-10 海岛Blog

试题编号： 201909-4
试题名称： 推荐系统
时间限制： 5.0s
内存限制： 512.0MB

问题链接：CCF201909-4 推荐系统
问题简述：（略）
问题分析：模拟题，不解释。
程序说明：（略）
参考链接：（略）
题记：（略）

100分的C++语言程序如下：

/* CCF201909-4 推荐系统 */

#include <bits/stdc++.h>

using namespace std;

const int M = 50;
int a[M], cnt[M + 1];
vector<int> choose[M + 1];

struct Goods {
    int type;
    int id;
    int score;
    bool operator < (const Goods &a) const {
        return score == a.score ? (type == a.type ? id < a.id : type < a.type) : score > a.score;
    }
};

struct DelGoods {
    int type;
    int id;
    bool operator < (const DelGoods &a) const {
        return type == a.type ? id < a.id : type < a.type;
    }
};

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    set<Goods> g;
    set<DelGoods> d;

    int m, n, type, id, score;
    cin >> m >> n;
    for (int i = 1; i <= n; i++) {
        cin >> id >> score;
        for (int j = 0; j < m; j++)
            g.insert(Goods{j, id, score});
    }

    int num, op, k;
    cin >> num;
    for (int i = 1; i <= num; i++) {
        cin >> op;
        if (op == 1) {        // 增加
            cin >> type >> id >> score;
            g.insert(Goods{type, id, score});
        } else if (op == 2) {     // 删除
            cin >> type >> id;
            d.insert(DelGoods{type, id});
        } else if (op == 3) {       // 查询
            memset(cnt, 0, sizeof cnt);
            for (int j = 0; j < m; j++) choose[j].clear();

            cin >> k;
            for (int j = 0; j < m; j++) cin >> a[j];

            for (set<Goods>::iterator iter = g.begin(); cnt[M] < k && iter != g.end();) {
                if (cnt[iter->type] < a[iter->type]) {
                    if (d.find(DelGoods{iter->type, iter->id}) != d.end())
                        g.erase(iter++);
                    else {
                        cnt[iter->type]++;
                        cnt[M]++;
                        choose[iter->type].push_back(iter->id);
                        iter++;
                    }
                } else
                    iter++;
            }

            // 输出结果
            for (int j = 0; j < m; j++) {
                if (cnt[j] == 0) cout << -1;
                else {
                    for(vector<int>::iterator iter = choose[j].begin(); cnt[M] <= k && iter != choose[j].end(); iter++)
                        cout << *iter << " ";
                }
                cout << "\\n";
            }
        }
    }

    return 0;
}

100分的C++语言程序如下：

/* CCF201909-4 推荐系统 */

#include <bits/stdc++.h>

using namespace std;

const int M = 50;
int a[M], cnt[M];

struct Goods {
    int type;
    int id;
    int score;
    bool operator < (const Goods &a) const {
        return score == a.score ? (type == a.type ? id < a.id : type < a.type) : score > a.score;

    }
};

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    set<Goods> g;
    map<pair<int, int>, int> mp;

    int m, n, type, id, score;
    cin >> m >> n;
    for (int i = 1; i <= n; i++) {
        cin >> id >> score;
        for (int j = 0; j < m; j++) {
            g.insert(Goods{j, id, score});
            mp[make_pair(j, id)] = score;
        }
    }

    int num, op, k;
    cin >> num;
    for (int i = 1; i <= num; i++) {
        cin >> op;
        if (op == 1) {        // 增加
            cin >> type >> id >> score;
            mp[make_pair(type, id)] = score;
            g.insert(Goods{type, id, score});
        } else if (op == 2) {     // 删除
            cin >> type >> id;
            score = mp[make_pair(type, id)];
            g.erase(Goods{type, id, score});
        } else if (op == 3) {       // 查询
            memset(cnt, 0, sizeof cnt);
            cin >> k;
            for (int j = 0; j < m; j++) cin >> a[j];

            vector<int> v[m];
            int sum = 0;
            for (set<Goods>::iterator iter = g.begin(); iter != g.end(); iter++) {
                type = iter->type;
                if (sum < k) {
                    if (cnt[type] < a[type]) {
                        sum++;
                        cnt[type]++;
                        v[type].push_back(iter->id);
                    }
                } else
                    break;

                bool flag = true;
                for (int j = 0; j < m; j++)
                    if (cnt[j] != a[j]) {
                        flag = false;
                        break;
                    }
                if (flag) break;
            }

            for (int j = 0; j < m; j++) {
                if (v[j].size() == 0) cout << -1;
                else {
                    for(int l = 0; l < (int)v[j].size(); l++)
                        cout << v[j][l] << " ";
                }
                cout << "\\n";
            }
        }
    }

    return 0;
}