藍橋杯-基礎練習-Sine之舞（Java）

An和Sn都用遞歸的思路求解會好理解一些

import java.util.Scanner;

public class Main{
    public static void main(String[] args){

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        scanner.close();

        System.out.println(getSn(n, n));
    }

    private static String getSn(int curr, int n){
        if(curr == 1)
            return String.format("%s+%d", getAn(1), n);
        return String.format("(%s)%s+%d", getSn(curr - 1, n), getAn(curr), n - curr + 1);
    }

    private static String getAn(int n){
        if(n == 1)
            return "sin(1)";

        StringBuilder sbResult = new StringBuilder(getAn(n - 1));
        for(int i = 0; i < n - 1; i++){
            sbResult.deleteCharAt(sbResult.length() - 1);
        }
        sbResult.append((n % 2 == 0 ? "-" : "+")  + "sin(" + n + ")");
        for(int i = 0; i < n - 1; i++){
            sbResult.append(")");
        }
        return sbResult.toString();
    }
}