题解 | #合并表记录#

import java.util.Scanner;
import java.util.TreeMap;
import java.util.Map;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        Map<Integer,Integer> map=new TreeMap<Integer,Integer>();
        int len=in.nextInt();
        while (in.hasNextInt()) {
          int key=in.nextInt();
          int value=in.nextInt();
          if(map.get(key)!=null){
            value=value+map.get(key);
          }
          map.put(key,value);
        }
        for(int key:map.keySet()){
            System.out.println(key+" "+map.get(key));
        }
    }
}