题解 | #合并表记录#

import java.util.Scanner;
import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        TreeMap<Integer,Integer> map = new TreeMap<Integer,Integer>();
        int n = scanner.nextInt();
        for(int i = 0;i < n;i++){
            int key = scanner.nextInt();
            int value = scanner.nextInt();
            if(map.containsKey(key)) {
                map.put(key,map.get(key)+value);
            }else {
                map.put(key,value);
            }
        }
        for(Integer k : map.keySet()){
                System.out.println(k + " " + map.get(k));
            }
        }
    }