1025 PAT Ranking (25分)

题目

有n个考场，每个考场有若干数量的考生。现在给出各个考场中考生的准考证号与分数,要求将所有考生按分数从高到低排序，并按顺序输出所有考生的准考证号排名、考场号以及考场内排名。

学到的东西

cmp函数
与sort函数相匹配

bool cmp(Student a, Student b){
	if(a.score != b.score) return a.score > b.score;	//分数从高到低 
	else return a.id < b.id;	//分数相等，准考证号从小到大 
}

排名写法
如 1，1，3，3，5这种排名

	stu[0].r = 1;
	for(int i = 1; i < n; i++)
	{
		if(stu[i].score == stu[i-1].score)
			stu[i].r = stu[i-1].r;
		else
			stu[i].r = i + 1;
	}

或者

	r = 1;
	for(i = 0; i < stu_num; i++){
		if(i > 0 && stu[i].score != stu[i-1].score)
			r = i + 1;
		stu[i].total_rank = r;
	}

代码

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

struct Student{
	string id;			//准考证 
	int score;			//分数 
	int location_number;//考场号 
	int local_rank;		//考场内排名 
	int total_rank;		//总排名 
}stu[30000];

bool cmp(Student a, Student b){
	if(a.score != b.score) return a.score > b.score;	//分数从高到低 
	else return a.id < b.id;	//分数相等，准考证号从小到大 
}


int main()
{
	int i,j,n,Pindex = 0;
	cin >> n;
	int stu_num = 0, k, m, r;	//stu_num为总学生数 
	for(i = 0; i < n; i++){
		cin >> k;
		/*输入每个学生信息 */
		for(j = 0; j < k; j++){
			cin >> stu[Pindex].id >> stu[Pindex].score;
			stu[Pindex].location_number = i + 1;			//考场号 
			Pindex++;
		}
		/*考场内部排序*/
		sort(stu + stu_num, stu + stu_num + k, cmp);
		r = 1;
		for(j = stu_num, m = 0; j < stu_num + k; j++, m++){
			if(j > stu_num && stu[j].score != stu[j-1].score)
				r = m + 1;
			stu[j].local_rank = r;
		}
		stu_num += k;	//总人数 
	}
	/*总人数按分数排序*/
	sort(stu, stu + stu_num, cmp);
	r = 1;
	for(i = 0; i < stu_num; i++){
		if(i > 0 && stu[i].score != stu[i-1].score)
			r = i + 1;
		stu[i].total_rank = r;
	}
	/*输出*/
	cout << stu_num << "\n";
	for(i=0; i<stu_num; i++){
		cout << stu[i].id << " " << stu[i].total_rank << " " << stu[i].location_number << " " << stu[i].local_rank << "\n";
	}
	return 0;
}