题解 | #合并表记录#

import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int tableIndex = scanner.nextInt();

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

        for (int i = 0; i < tableIndex; i++) {

            int index = scanner.nextInt();
            int value = scanner.nextInt();

            if (treeMap.containsKey(index)){
                treeMap.put(index, treeMap.get(index)+value);
            } else {
                treeMap.put(index, value);
            }
        }

        Set<Integer> integers = treeMap.keySet();

        for (Integer index : integers) {
            System.out.println(index+" "+treeMap.get(index));
        }

    }
}