2023蓝桥杯大赛省赛Java大学B组 阶乘求和

package test;
 
import java.util.Scanner;
 
public class Main{
  public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    //要取余就要在每一次可能溢出的运算处取余
    long sum=0;
    for(long i=1;i<=100;i++) {
      long ans=1;
      for(long j=2;j<=i;j++) {
        ans*=j;
        ans%=1000000000;
      }
      sum+=ans;
      sum%=1000000000;
    }
    long a=sum%1000000000;
    System.out.print(a);
  }
}