题解 | #合并表记录#

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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        TreeMap<Integer,Integer> map = new TreeMap<>();
        for(int i=0; i<n; i++){
            int key = sc.nextInt();
            int value = sc.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));
        }
    }
}