演算法學習之路|PATRanking

Programming Ability Test (PAT) is organized by the College of Computer Science and Technology of Zhejiang University. Each test is supposed to run simultaneously in several places, and the ranklists will be merged immediately after the test. Now it is your job to write a program to correctly merge all the ranklists and generate the final rank.
Input Specification:
Each input file contains one test case. For each case, the first line contains a positive number N (<=100), the number of test locations. Then N ranklists follow, each starts with a line containing a positive integer K (<=300), the number of testees, and then K lines containing the registration number (a 13-digit number) and the total score of each testee. All the numbers in a line are separated by a space.
Output Specification:
For each test case, first print in one line the total number of testees. Then print the final ranklist in the following format:
registration_number final_rank location_number local_rank
The locations are numbered from 1 to N. The output must be sorted in nondecreasing order of the final ranks. The testees with the same score must have the same rank, and the output must be sorted in nondecreasing order of their registration numbers.
Sample Input:
2
5
1234567890001 95
1234567890005 100
1234567890003 95
1234567890002 77
1234567890004 85
4
1234567890013 65
1234567890011 25
1234567890014 100
1234567890012 85
Sample Output:
9
1234567890005 1 1 1
1234567890014 1 2 1
1234567890001 3 1 2
1234567890003 3 1 2
1234567890004 5 1 4
1234567890012 5 2 2
1234567890002 7 1 5
1234567890013 8 2 3
1234567890011 9 2 4
解題思路:
每個考場有若干的考生，共有n個考場，要求將學生按照分數大小從高到底排序，並按要求輸出資訊。
定義一個結構體來儲存每個學生的資訊，包括考場排名和總排名。

#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
struct stu{
    long long id;
    int grade,ln,lr,gr;
};

bool cmp(stu a,stu b){
    if(a.grade!=b.grade)return a.grade>b.grade;
    else{
        return a.id<b.id;
    }
}
int main(){
    int n;
    scanf("%d",&n);
    int m;
    vector<stu>fin;
    for(int i=0;i<n;i++){
        scanf("%d",&m);
        vector<stu>tem(m);
        for(int j=0;j<m;j++){
            scanf("%lld %d",&tem[j].id,&tem[j].grade);
            tem[j].ln=i+1;
        }
        sort(tem.begin(),tem.end(),cmp);
        tem[0].lr=1;
        fin.push_back(tem[0]);
        for(int j=1;j<m;j++){
            tem[j].lr=j+1;
            if(tem[j].grade==tem[j-1].grade){
                tem[j].lr=tem[j-1].lr;
            }
            fin.push_back(tem[j]);
        }
    }
    sort(fin.begin(),fin.end(),cmp);
    fin[0].gr=1;
    for(int i=1;i<fin.size();i++){
        fin[i].gr=i+1;
        if(fin[i].grade==fin[i-1].grade){
            fin[i].gr=fin[i-1].gr;
        }
    }
    printf("%d
",fin.size());
    for(int i=0;i<fin.size();i++){
        printf("%013lld %d %d %d
",fin[i].id,fin[i].gr,fin[i].ln,fin[i].lr); 
    }
    return 0;
}