题解 | 合并表记录

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 scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        Map<Integer,Integer> map = new TreeMap<>();
        while(n-- > 0){
            int key = scanner.nextInt();
            int value = scanner.nextInt();
            if(map.containsKey(key)){
                map.put(key,map.get(key)+value);
            }else{
                map.put(key,value);
            }
        }
        for(Map.Entry entrySet:map.entrySet()){
            System.out.println(entrySet.getKey() + " " + entrySet.getValue());
        }
    }
}