题目来源：PAT乙级真题 1032 挖掘机技术哪家强 (20 分)

import java.util.*;
public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Map<Integer,Integer> map = new HashMap<>();
        int max = -1;
        int max_num = -1;
        for(int i = 0 ; i < n ; i++) {
            int num = sc.nextInt();
            int score = sc.nextInt();
            if(map.containsKey(num)) {
                map.put(num, map.get(num) + score);
            } else {
                map.put(num, score);
            }
            if(max < map.get(num)) {
                max = map.get(num);
                max_num = num;
            }
        }
        System.out.println(max_num + " " + max);
    }
}

有一组数据会运行超时，目前没办法，留待补充……