数学知识求序列和

就是等差数列求和，推出a1 = 2N-i(i-1) / 2i即可。
i就是大等于L的长度。a1是第一项。

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int L = sc.nextInt();
        boolean flag = false;
        for(int i = L; i <= 100; i++){
            if((2*N + i - i*i) % (2 * i) == 0){
                flag = true;
                int a1 = (2*N + i - i*i) / (2 * i);
                for(int j = 0; j < i - 1; j++){
                    int a = a1 + j;
                    System.out.print(a + " ");
                }
                System.out.println(a1 + i - 1);
                break;
            }
        }
        if(!flag){
            System.out.println("No");    
        }

    }
}