题解 | #合并表记录#

import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
import java.util.Scanner;

// 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);

        Map<Integer, Integer> data = new TreeMap();
        int count = Integer.valueOf(in.nextLine()).intValue();
        while (true) {
            String line = "";
            try {
                line = in.nextLine();
            } catch (Exception e) {

            }
            if (line.length() == 0) {
                break;
            }
            String[] lineA = line.split(" ");
            if (data.containsKey(Integer.valueOf(lineA[0]))) {
                Integer value = Integer.valueOf(lineA[1]) + data.get(Integer.valueOf(lineA[0]));
                data.put(Integer.valueOf(lineA[0]), value);
                continue;
            }
            data.put(Integer.valueOf(lineA[0]), Integer.valueOf(lineA[1]));
        }

        data.forEach((key, value) -> {
            System.out.println(key + " " + value);
        });
    }
}