题解 | #合并表记录#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int input = 0;
        Map<Integer, Integer> map = new HashMap<>();
        while (input == 0) {
            input = in.nextInt();
            in.nextLine();
        }
        for (int i = 0; i < input; i++) {
            String s1 = in.nextLine();
            int i1 = s1.indexOf(" ");
            int num1 = Integer.parseInt(s1.substring(0, i1)) ;
            int num2 = Integer.parseInt(s1.substring(i1 + 1));
            if (map.containsKey(num1)) {
                map.put(num1, map.get(num1) + num2);
            } else {
                map.put(num1, num2);
            }
        }
        Set treeSet = new TreeSet(map.keySet());
        treeSet.forEach(item -> {System.out.println(item+ " "+ map.get(item));});
    }
}