題目：給定一個小於7000的數，求其階乘。

import java.util.ArrayList;
import java.util.List;

public final class Main {

    static Integer num = 7000;
    static List<Integer> result = new ArrayList<Integer>();
    public static void main(String[] args) {
        for (int i = 1; i < num + 1; i++) {
            if
 
 (1 == i) {
                result.add(i);
            } else {
                for (int y = 0; y < result.size(); y++) {
                    result.set(y, result.get(y) * i);
                }
            }
            for (int z = 0; z < result.size(); z++) {
                Integer current = result.get(z);

                if
 
 (current > 9) {
                    Integer carry = current / 10;
                    Integer remainder = current % 10;

                    result.set(z, remainder);

                    Integer next = 0;
                    if (result.size() - 1 == z) {
                        result.add(0);
                    } else
 
 {
                        next = result.get(z + 1);
                    }

                    result.set(z + 1, next + carry);
                }
            }
        }
        System.out.println(result.size());
        for (int i = result.size() - 1; i >= 0; i--) {
            System.out.print(result.get(i));
        }
    }
}

相關：之所以要求給定一個小於7000的數字是因為int型的資料型別儲存資料的上限決定的，不同的處理器是不同的