#include <bits/stdc++.h> using namespace std; typedef long long ll; const int N = 6e5+10; const int mod = 1e9+7; ll a[N]; int n,k; ll fac[N]; ll inv[N]; ll qpow(ll a,ll b,ll p) { ll res = 1; for(;b;b>>=1) { if(b&1) { res = res*a%p; } a = a*a%p; } return res; } ll C(ll n,ll m) { retur...