181.小明的难题

#include<stdio.h>int main(){    int t,i,n;    scanf("%d",&t);    while(t--)    {        long long k=1,sum=0;        scanf("%d",&n);        if(n==1)            printf("%d\n",n);        else        {            for(i=2;i<=n;i++)            {                k*=i;                if(i%2==0)                    sum+=k;                else                    sum-=k;            }            printf("%lld\n",sum+1);        }    }}