题解 | #合并表记录#

import java.util.Scanner;

import java.util.*;
import java.io.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        String str;

        while ((str = bf.readLine()) != null) {
             int number = Integer.parseInt(str);
            TreeMap<Integer,Integer> map=new TreeMap<>(Integer::compareTo);
            String s = bf.readLine();
            map.put(Integer.parseInt(s.split(" ")[0]),Integer.parseInt(s.split(" ")[1]));
            while (number>1){
                String s1 = bf.readLine();
                Integer key = Integer.parseInt(s1.split(" ")[0]);
                if (map.containsKey(key)){
                    Integer count = map.get(key);
                     count = count + Integer.parseInt(s1.split(" ")[1]);
                    map.put(key,count);
                    number--;
                    continue;
                }
                map.put(key,Integer.parseInt(s1.split(" ")[1]));
                number--;
            }
            StringBuilder sb=new StringBuilder();
            map.forEach((key,value)->sb.append(key).append(" ").append(value).append("\n"));
            System.out.println(sb.toString());
        }
    }
}