求助为啥显示WA

P1009 [NOIP1998 普及组] 阶乘之和

boss_luke @ 2023-09-18 22:39:10

public class P1009 {

    public static void main(String[] args) {
        // TODO 自动生成的方法存根
        Scanner sc = new Scanner(System.in);
        int number = sc.nextInt();
        String result = "1";
        for(int m = 2 ; m <= number; m++) {
            String num1 = Integer.toString(m);
            result = multiply(result,num1);

        }

        System.out.print(result);

    }   
    public static String multiply(String num1, String num2) {
        int len1 = num1.length();
        int len2 = num2.length();
        int[] result = new int[len1 + len2];

        for (int i = len1 - 1; i >= 0; i--) {
            int digit1 = num1.charAt(i) - '0';

            for (int j = len2 - 1; j >= 0; j--) {
                int digit2 = num2.charAt(j) - '0';

                int product = digit1 * digit2;

                int pos1 = i + j;
                int pos2 = i + j + 1;

                int sum = product + result[pos2];

                result[pos1] += sum / 10;
                result[pos2] = sum % 10;
            }
        }

        StringBuilder sb = new StringBuilder();
        for (int digit : result) {
            if (!(sb.length() == 0 && digit == 0)) {
                sb.append(digit);
            }
        }

        return sb.length() == 0 ? "0" : sb.toString();
    }}

by boss_luke @ 2023-09-18 22:39:43

大神帮我看看我测了本地没问题啊呜呜


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