PAT甲刷题——U4.3

注意：允许转载，但转载请注明作者和出处

最重要：关于同分同名次总结

#include <iostream>
#include <algorithm>
using namespace std;
int main()
{
    int a[] = {99, 99, 98, 97, 96, 96, 96, 95};
    int len = sizeof(a) / sizeof(a[0]);
    // cout << len << endl;
    // // 方法1：for遍历-----得到所有分数对应的名次
    // int rank[len] = {0};
    // for (int i = 0; i < len; i ++)
    // {
    //     if (!i || a[i] != a[i - 1]) rank[i] = i + 1;
    //     else rank[i] = rank[i - 1];
    // }
    // for (int i = 0; i < len; i ++) cout << rank[i] << ' ';
    // puts("");
    // // result:1 1 3 4 5 5 5 8 
    // 方法2：二分法-----得到某个分数对应名词
    reverse(a, a + len);
    int score;
    cin >> score;
    int l = 0, r = len - 1;
    while (l < r)
    {
        int mid = l + r + 1 >> 1;
        if (a[mid] <= score) l = mid;
        else r = mid - 1;
    }
    cout << len - l << endl;
    return 0;
}

1502. PAT排名（难）

题目

解析

这个题写的我极其痛苦。。。debug也极其痛苦。。。

答案

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
const int N = 310;
struct Grade
{
    string id;
    int grade, local_num;
    int local_rank, final_rank;
    bool operator< (const Grade &t) const
    {
        if (grade != t.grade) return grade > t.grade;
        return id < t.id;
    }
};
vector<Grade> place[N];
vector<Grade> all;

int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i ++)
    {
        int k;
        cin >> k;
        for (int j = 0; j < k; j ++)
        {
            string id;
            int grade;
            cin >> id >> grade;
            place[i].push_back({id, grade, i});
        }
        sort(place[i].begin(), place[i].end());
        // 某分数在有序数组中得到对应名次，同分同名次
        auto& p = place[i];
        for (int j = 0; j < k; j ++)
        {
            if (!j || p[j].grade != p[j - 1].grade)
                p[j].local_rank = j + 1;
            else p[j].local_rank = p[j - 1].local_rank;
            // cout << p[j].local_rank << endl;
        }
        
    }

    for (int i = 1; i <= n; i ++)
    {
        auto p = place[i];
        // printf("place[%d]的长度是%d\n", i, p.size());
        for (auto pp : p) all.push_back(pp);
    }
    sort(all.begin(), all.end());
    for (int i = 0; i < all.size(); i ++)
    {
        if (!i || all[i].grade != all[i - 1].grade)
            all[i].final_rank = i + 1;
        else all[i].final_rank = all[i - 1].final_rank;
    }
    
    cout << all.size() << endl;
    for (auto a : all)
        cout << a.id << ' ' << a.final_rank << ' ' << a.local_num << ' ' << a.local_rank << endl;
    
    return 0;
}