题解 | #合并表记录#

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

// 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) {
        Scanner in = new Scanner(System.in);
        TreeMap<Long,Long> map = new TreeMap<Long,Long>();
        int n = in.nextInt();
        long x,y;
        while(n>0){
            x = in.nextLong();
            y = in.nextLong();
            if(map.containsKey(x)){
                map.put(x,map.get(x)+y);
            }else{
                map.put(x,y);
            }
            n--;
        }
        for(Long key : map.keySet()){
            System.out.println(key+" "+map.get(key));
        }
    }
}