#include using namespace std; //入力が必ず-mod<=a //mod<2^30. struct modint{ //mod変更が不可能. public: long long v; static void setmod(int m){} //飾り. static constexpr long long getmod(){return mod;} modint():v(0){} template modint(T a):v(a){if(v < 0) v += mod;} long long val()const{return v;} modint &operator=(const modint &b) = default; modint &operator+()const{return (*this);} modint operator-()const{return modint(0)-(*this);} modint operator+(const modint b)const{return modint(v)+=b;} modint operator-(const modint b)const{return modint(v)-=b;} modint operator*(const modint b)const{return modint(v)*=b;} modint operator/(const modint b)const{return modint(v)/=b;} modint &operator+=(const modint b){ v += b.v; if(v >= mod) v -= mod; return *this; } modint &operator-=(const modint b){ v -= b.v; if(v < 0) v += mod; return *this; } modint &operator*=(const modint b){v = v*b.v%mod; return *this;} modint &operator/=(modint b){ //b!=0 mod素数が必須. assert(b.v != 0); (*this) *= b.pow(mod-2); return *this; } modint pow(long long n)const{ modint ret = 1,p = v; if(n < 0) p = p.inv(),n = -n; while(n){ if(n&1) ret *= p; p *= p; n >>= 1; } return ret; } modint inv()const{return pow(mod-2);} //素数mod必須. modint &operator++(){*this += 1; return *this;} modint &operator--(){*this -= 1; return *this;} modint operator++(int){modint ret = *this; *this += 1; return ret;} modint operator--(int){modint ret = *this; *this -= 1; return ret;} friend bool operator==(const modint a,const modint b){return a.v==b.v;} friend bool operator!=(const modint a,const modint b){return a.v!=b.v;} friend bool operator<(const modint a,const modint b){return a.v=(const modint a,const modint b){return a.v>=b.v;} friend bool operator>(const modint a,const modint b){return a.v>b.v;} friend ostream &operator<<(ostream &os,const modint a){return os<>(istream &is,modint &a){ //入力はmodをとってくれる. long long x; is >> x; x %= mod; a = modint(x); return is; } }; using mint = modint<998244353>; const long long mod = 998244353; int main(){ ios_base::sync_with_stdio(false); cin.tie(nullptr); return 0; int Limit = 200200; //Limit->必要なサイズ fac->x! facinv->1/x! inv->1/x. vector fac(Limit+1,1),facinv(Limit+1); { int mod = mint::getmod(),invstart = min(mod-1,Limit); for(int i=1; i<=Limit; i++) fac.at(i) = fac.at(i-1)*i; facinv.at(invstart) = fac.at(invstart).inv(); for(int i=invstart-1; i>=0; i--) facinv.at(i) = facinv.at(i+1)*(i+1); } vector inv(Limit+1); for(int i=1; i<=Limit; i++) inv.at(i) = fac.at(i-1)*facinv.at(i); //必要なら解放. auto nCr = [&](int n,int r) -> mint { if(n < r || r < 0 || n < 0) return 0; return fac.at(n)*facinv.at(r)*facinv.at(n-r); }; int T; cin >> T; while(T--){ int N,L; cin >> N >> L; vector D(N); for(auto &d : D) cin >> d; if(L%2 || N <= 3){ mint ans = 0; for(int i=0; i