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);
        while (in.hasNext()){
            int N = Integer.parseInt(in.nextLine());      
            Map<Integer,Integer> res = new HashMap<>();
            int[] sum = new int[N];
            for (int i=0;i<N;i++){
                String str = in.nextLine();
                String[] strings = str.split(" ");
                sum[i] = Integer.parseInt(strings[0]);
                if (res.get(sum[i])==null) res.put(sum[i],Integer.parseInt(strings[1]));
                else res.put(sum[i],Integer.parseInt(strings[1])+res.get(sum[i]));
            }
            for (int i=0;i<N-1;i++){
                for(int j = i+1;j<N;j++){
                    if (sum[i]>sum[j]) {
                        int ll = sum[i];
                        sum[i] = sum[j];
                        sum[j] = ll;
                    }
                }
            }
            for (int i=0;i<N;i++){
                if (i==0||sum[i]!=sum[i-1]) System.out.println(sum[i]+" "+res.get(sum
                [i]));
            }
        }
    }
}