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);
        int n = in.nextInt();
        int arr[] = new int[n];
        int b[] = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = in.nextInt();
            b[i] = in.nextInt();
        }
        TreeMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
        int s;
        for (int i = 0; i < n; i++) {
            s = arr[i];
            if (map.containsKey(s)) {
                map.put(s, map.get(s) + b[i]);
            } else {
                map.put(s, b[i]);
            }
        }
        for (int d : map.keySet()) {
            System.out.println(d+" "+map.get(d));
        }
    }
}