#include<bits/stdc++.h>usingnamespacestd;staticconstintMOD=1000000007;//预先全局存放阶乘与逆阶乘的数组staticconstintMAXN=100000;//根据题意，n最多10^5longlongfact[MAXN+1],invFact[MAXN+1];//快速幂，用于求x^y%MODlonglongfastPow(lo