题解 | #合并表记录#

import java.util.*;


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