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 in = new Scanner(System.in);
        int arrSize = in.nextInt();
        int[][] arrs = new int[arrSize][2];
        int i = 0;
        in.nextLine();
        Map<Integer, Integer> dataMap =new HashMap();
        while(i<arrSize){
            int key = in.nextInt();
            int value = in.nextInt();
            dataMap.put(key, dataMap.getOrDefault(key,0)+value);
            i++;
        }
        dataMap.entrySet().stream().sorted(Comparator.comparing(Map.Entry::getKey)).forEach(a-> System.out.println(a.getKey()+" "+a.getValue()));
    }
}