题解 | 尼科彻斯定理

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
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 first = n * n - n + 1;
        StringBuilder sb = new StringBuilder();
        sb.append(first+"+");
        for (int i = 1; i < n; i++) {
            first = first + 2;
            if (i == n - 1) {
                sb.append(first);
            } else {
                sb.append(first + "+");
            }
        }
        System.out.println(sb.toString());
    }
}