题解 | #合并表记录#

//TreeMap自动排序去重，key已存在就做加法更新value

import java.util.TreeMap;
public class Main {
    public static void main(String[] args) {
        TreeMap<Integer,Integer> treeMap = new TreeMap<>();
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        for (int i = 0;i < n;i++){
            int a = sc.nextInt();
            int b = sc.nextInt();
            if (treeMap.containsKey(a)){
                treeMap.put(a,treeMap.get(a)+b);
            }else {
                treeMap.put(a,b);
            }
        }
        for (int i:treeMap.keySet()
             ) {
            System.out.println(i+" "+treeMap.get(i));
        }
    }
}