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);
        while (in.hasNext()) {
            int count = in.nextInt();

            TreeMap<Integer, Integer> treeMap = new TreeMap<>();

            for (int i = 0; i < count; i++) {
                int key = in.nextInt();
                int value = in.nextInt();

                if (treeMap.containsKey(key)) {
                    Integer integer = treeMap.get(key);
                    int i1 = integer + value;
                    treeMap.put(key, i1);
                } else {
                    treeMap.put(key, value);
                }

            }

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

    }
}