题解 | #合并表记录#

import java.util.*;

public class Main{
    
    public static void main(String[] args) {
        merge();
    }

    public static void merge(){
        HashMap<Integer,Integer> result = new HashMap<>();
        Scanner sc = new Scanner(System.in);
        sc.nextLine();
        while(sc.hasNextLine()){
            String s = sc.nextLine();
            String[] split = s.split(" ", -1);
            int key = Integer.parseInt(split[0]);
            int value = Integer.parseInt(split[1]);
            result.put(key,result.containsKey(key)?value+result.get(key):value);
        }
        result.keySet().stream().sorted(Integer::compareTo).forEach(k-> System.out.println(k+" "+result.get(k)));
    }
}