题解 | #合并表记录#

import java.util.*;
import java.io.*;

// 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) throws IOException {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        TreeMap<Integer, Integer> map = new TreeMap<>();
        for (int i = 0; i < n; i++) {
           int Key=scanner.nextInt();
            int Value=scanner.nextInt();
            if(i !=0){
                if(duplicateRemoval(map,Key,Value)){
                    map.put(Key,Value+map.get(Key));
                }else {
                    map.put(Key,Value);
                }
            }else {
                map.put(Key,Value);
            }
        }
        Set<Integer> integers = map.keySet();
        for (Integer integer : integers) {
            System.out.println(integer+" "+map.get(integer));
        }

    }
    public  static boolean duplicateRemoval(TreeMap map,int k,int v){
        Set set = map.entrySet();
        Iterator iterator = set.iterator();
        while (iterator.hasNext()) {
            Map.Entry next =(Map.Entry)  iterator.next();
            int key =(int) next.getKey();
            if(key==k){
                return true;
            }
        }
        return false;
    }
  
}