题解 | #合并表记录#

利用TreeMap自排序 进行处理数据
然后直接输出即可

import java.util.*;
public class Main {
    public static void main(String[] args){
        TreeMap<Integer, Integer> map = new TreeMap<>();
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        for(int i = 0; i < n; i++){
            int index = scanner.nextInt();
            int value = scanner.nextInt();
            map.put(index, map.getOrDefault(index, 0) + value);
        }

        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
            System.out.println(entry.getKey() + " " + entry.getValue());
        }
    }
}