PTA -- A1025

 

題意及思路

題意：至關於考試排名，若是成績同樣按學號（從小到大），不然按成績從高到低排名。

思路：略。

注：用java寫的超時了（這題時限爲300ms）。說明java比較慢。

心得：這題讓我對Java比較器的用法加深了，此外對c++的sort排序也理解了一些。

 

代碼（C++）

#include<bits/stdc++.h>

using namespace std;

typedef struct{
    char id[15];
    int score;
    int location_number;
    int local_rank;
}Stu;

const int MAXSIZE = 30010;
Stu stus[MAXSIZE];

bool cmp(Stu a,Stu b){
    if(a.score!=b.score) return a.score>b.score; //按成績排 
    else return strcmp(a.id,b.id)<0; //按id排 
}

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(0);
    int n,k,total; // total:總人數 
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> k;
        for(int j=0;j<k;j++){
            cin >> stus[total].id >> stus[total].score;
            stus[total].location_number = i;
            total++;
        }
        sort(stus+total-k,stus+total-k+k,cmp);
        //設置local_rank 
        stus[total-k].local_rank = 1; //將該考場的第一名的本場排名置爲1
        for(int j=total-k+1;j<total;j++){
            if(stus[j].score == stus[j-1].score){
                stus[j].local_rank = stus[j-1].local_rank;
            }else{
                stus[j].local_rank = j-(total-k) + 1; //下標減去首地址，再+1 
            }
        } 
    }
    cout << total << endl;
    sort(stus,stus+total,cmp);
    //設置rank-總排名
    int rank = 1;
    for(int i=0;i<total;i++){
        if(i>0 && stus[i].score!=stus[i-1].score){
            rank = i+1; //當考試的成績與上一個同窗的成績不相同時，置其rank爲當前總人數 
        }
        printf("%s ",stus[i].id);
        printf("%d %d %d\n",rank,stus[i].location_number,stus[i].local_rank);
    } 
    return 0;
}

 

代碼（Java）

package com.pta.java;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class A1025 {
    private static ArrayList<acmer> li = new ArrayList<>();
    private static ArrayList<acmer> mi = new ArrayList<>();

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        for (int i = 1; i <= n; i++) {
            int k = in.nextInt();
            for (int j = 1; j <= k; j++) {
                String registration_number = in.next();
                int score = in.nextInt();
                acmer a = new acmer();
                a.registration_number = registration_number;
                a.score = score;
                a.location_number = i;
                mi.add(a);
            }
            // sort
            Collections.sort(mi);
            // set local_rank
            mi.get(0).local_rank = 1;
            for (int j = 1; j < k; j++) {
                if (mi.get(j).score == mi.get(j - 1).score) {
                    mi.get(j).local_rank = mi.get(j - 1).local_rank;
                } else {
                    mi.get(j).local_rank = j + 1;
                }
            }
            li.addAll(mi);
            mi.clear();
        }
        // sort all
        Collections.sort(li);
        int len = li.size();
        System.out.println(len);
        // set final_rank
        int rank = 1;
        for (int i = 0; i < len; i++) {
            acmer a = li.get(i);
            if (i > 0 && a.score != li.get(i - 1).score) {
                rank = i + 1;
            }
            System.out.print(a.registration_number + " ");
            System.out.println(rank + " " + a.location_number + " " + a.local_rank);
        }
        in.close();
    }
}

class acmer implements Comparable<acmer> {
    String registration_number;
    int location_number;
    int local_rank;
    int score;

    public int compareTo(acmer o) {
        if (this.score == o.score) {
            return this.registration_number.compareTo(o.registration_number);
        } else {
            return -(this.score - o.score);
        }
    }
}