题解 | 合并表记录

import java.util.Scanner;

// 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[][] a = new int[n][2];
        int[][] b = new int[n][2];
        int len = 0;  //记录b的真实长度

        for (int i = 0; i < n; i++) {
            a[i][0] = in.nextInt();
            a[i][1] = in.nextInt();
        }

        //把a按索引排序
        for (int i = 0; i < n-1; i++) {
            for (int j = i+1; j < n; j++) {
                if (a[i][0] > a[j][0]) {
                    b[0][0] = a[i][0];
                    b[0][1] = a[i][1];
                    a[i][0] = a[j][0];
                    a[i][1] = a[j][1];
                    a[j][0] = b[0][0];
                    a[j][1] = b[0][1];
                }
            }
        }

        b[0][0] = a[0][0];
        b[0][1] = a[0][1];
        for (int i = 1; i < n; i++) {
            if (b[len][0] == a[i][0]) {  //索引相同
                b[len][1] = b[len][1] + a[i][1];
                continue;
            }
            b[++len][0] = a[i][0];
            b[len][1] = a[i][1];
        }

        //输出b
        for (int i = 0; i <= len; i++) {
            System.out.println(b[i][0] + " " + b[i][1]);
        }
    }
}