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 sc = new Scanner(System.in);
        int n = sc.nextInt();//输入要输入键值对的个数
        TreeMap<Integer, String> tm = new TreeMap<>();
        int l = tm.size();
        for ( l=0 ; l < n; l++) {
            int s = Integer.parseInt(sc.next());
            String s1 = sc.next();
            if(tm.containsKey(s)){
                tm.put(s, String.valueOf(Integer.parseInt(tm.get(s))+Integer.parseInt(s1)));
            }else {
                tm.put(s, s1);
            }

        }
        Iterator<Map.Entry<Integer, String>> iterator = tm.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<Integer, String> entry = iterator.next();

            System.out.println(entry.getKey() + " " + entry.getValue());
        }
    }
}