#define _USE_MATH_DEFINES #include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) (v).begin(),(v).end() using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 998244353; // constexpr int MOD = 1000000007; constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1}; constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}; constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; template struct MInt { unsigned int v; MInt() : v(0) {} MInt(const long long x) : v(x >= 0 ? x % M : x % M + M) {} static constexpr int get_mod() { return M; } static void set_mod(const int divisor) { assert(divisor == M); } static void init(const int x = 10000000) { inv(x, true); fact(x); fact_inv(x); } static MInt inv(const int n, const bool init = false) { // assert(0 <= n && n < M && std::__gcd(n, M) == 1); static std::vector inverse{0, 1}; const int prev = inverse.size(); if (n < prev) { return inverse[n]; } else if (init) { // "n!" and "M" must be disjoint. inverse.resize(n + 1); for (int i = prev; i <= n; ++i) { inverse[i] = -inverse[M % i] * (M / i); } return inverse[n]; } int u = 1, v = 0; for (unsigned int a = n, b = M; b;) { const unsigned int q = a / b; std::swap(a -= q * b, b); std::swap(u -= q * v, v); } return u; } static MInt fact(const int n) { static std::vector factorial{1}; const int prev = factorial.size(); if (n >= prev) { factorial.resize(n + 1); for (int i = prev; i <= n; ++i) { factorial[i] = factorial[i - 1] * i; } } return factorial[n]; } static MInt fact_inv(const int n) { static std::vector f_inv{1}; const int prev = f_inv.size(); if (n >= prev) { f_inv.resize(n + 1); f_inv[n] = inv(fact(n).v); for (int i = n; i > prev; --i) { f_inv[i - 1] = f_inv[i] * i; } } return f_inv[n]; } static MInt nCk(const int n, const int k) { if (n < 0 || n < k || k < 0) return 0; return fact(n) * (n - k < k ? fact_inv(k) * fact_inv(n - k) : fact_inv(n - k) * fact_inv(k)); } static MInt nPk(const int n, const int k) { return n < 0 || n < k || k < 0 ? 0 : fact(n) * fact_inv(n - k); } static MInt nHk(const int n, const int k) { return n < 0 || k < 0 ? 0 : (k == 0 ? 1 : nCk(n + k - 1, k)); } static MInt large_nCk(long long n, const int k) { if (n < 0 || n < k || k < 0) return 0; inv(k, true); MInt res = 1; for (int i = 1; i <= k; ++i) { res *= inv(i) * n--; } return res; } MInt pow(long long exponent) const { MInt res = 1, tmp = *this; for (; exponent > 0; exponent >>= 1) { if (exponent & 1) res *= tmp; tmp *= tmp; } return res; } MInt& operator+=(const MInt& x) { if ((v += x.v) >= M) v -= M; return *this; } MInt& operator-=(const MInt& x) { if ((v += M - x.v) >= M) v -= M; return *this; } MInt& operator*=(const MInt& x) { v = static_cast(v) * x.v % M; return *this; } MInt& operator/=(const MInt& x) { return *this *= inv(x.v); } bool operator==(const MInt& x) const { return v == x.v; } bool operator!=(const MInt& x) const { return v != x.v; } bool operator<(const MInt& x) const { return v < x.v; } bool operator<=(const MInt& x) const { return v <= x.v; } bool operator>(const MInt& x) const { return v > x.v; } bool operator>=(const MInt& x) const { return v >= x.v; } MInt& operator++() { if (++v == M) v = 0; return *this; } MInt operator++(int) { const MInt res = *this; ++*this; return res; } MInt& operator--() { v = (v == 0 ? M - 1 : v - 1); return *this; } MInt operator--(int) { const MInt res = *this; --*this; return res; } MInt operator+() const { return *this; } MInt operator-() const { return MInt(v ? M - v : 0); } MInt operator+(const MInt& x) const { return MInt(*this) += x; } MInt operator-(const MInt& x) const { return MInt(*this) -= x; } MInt operator*(const MInt& x) const { return MInt(*this) *= x; } MInt operator/(const MInt& x) const { return MInt(*this) /= x; } friend std::ostream& operator<<(std::ostream& os, const MInt& x) { return os << x.v; } friend std::istream& operator>>(std::istream& is, MInt& x) { long long v; is >> v; x = MInt(v); return is; } }; using ModInt = MInt; // https://github.com/beet-aizu/library/blob/master/mod/mint.cpp template struct Mint{ inline static constexpr T mod = MOD; T v; Mint():v(0){} Mint(signed v):v(v){} Mint(long long t){v=t%MOD;if(v<0) v+=MOD;} Mint pow(long long k){ Mint res(1),tmp(v); while(k){ if(k&1) res*=tmp; tmp*=tmp; k>>=1; } return res; } static Mint add_identity(){return Mint(0);} static Mint mul_identity(){return Mint(1);} Mint inv(){return pow(MOD-2);} Mint& operator+=(Mint a){v+=a.v;if(v>=MOD)v-=MOD;return *this;} Mint& operator-=(Mint a){v+=MOD-a.v;if(v>=MOD)v-=MOD;return *this;} Mint& operator*=(Mint a){v=1LL*v*a.v%MOD;return *this;} Mint& operator/=(Mint a){return (*this)*=a.inv();} Mint operator+(Mint a) const{return Mint(v)+=a;} Mint operator-(Mint a) const{return Mint(v)-=a;} Mint operator*(Mint a) const{return Mint(v)*=a;} Mint operator/(Mint a) const{return Mint(v)/=a;} Mint operator+() const{return *this;} Mint operator-() const{return v?Mint(MOD-v):Mint(v);} bool operator==(const Mint a)const{return v==a.v;} bool operator!=(const Mint a)const{return v!=a.v;} static Mint comb(long long n,int k){ Mint num(1),dom(1); for(int i=0;i struct NTT{ inline static constexpr int md = bmds(X); inline static constexpr int rt = brts(X); using M = Mint; vector< vector > rts,rrts; void ensure_base(int n){ if((int)rts.size()>=n) return; rts.resize(n);rrts.resize(n); for(int i=1;i &as,bool f){ int n=as.size(); assert((n&(n-1))==0); ensure_base(n); for(int i=0,j=1;j+1>1;k>(i^=k);k>>=1); if(i>j) swap(as[i],as[j]); } for(int i=1;i multiply(vector as,vector bs){ int need=as.size()+bs.size()-1; int sz=1; while(sz multiply(vector as,vector bs){ vector am(as.size()),bm(bs.size()); for(int i=0;i<(int)am.size();i++) am[i]=M(as[i]); for(int i=0;i<(int)bm.size();i++) bm[i]=M(bs[i]); vector cm=multiply(am,bm); vector cs(cm.size()); for(int i=0;i<(int)cs.size();i++) cs[i]=cm[i].v; return cs; } }; int main() { constexpr int M = 299; NTT<2> ntt; int n, m; cin >> n >> m; vector a(n), b(n); REP(i, n) cin >> a[i]; REP(i, n) cin >> b[i]; vector dp(M * m * 2 + 1, 0); dp[M * m] = 1; REP(i, m) { int lb = -M, ub = M; for (int k = i; k < n; k += m) { chmax(lb, -b[k]); chmin(ub, a[k]); } vector ways(ub - lb + 1, 1); for (int k = i; k < n; k += m) { vector c(a[k] + 1, 0), d(b[k] + 1, 0); for (int j = 0; j <= a[k]; ++j) { c[j] = ModInt::nCk(a[k], j).v; } for (int j = 0; j <= b[k]; ++j) { d[b[k] - j] = ModInt::nCk(b[k], j).v; } const auto e = ntt.multiply(c, d); for (int j = lb; j <= ub; ++j) { ways[j - lb] = 1LL * ways[j - lb] * e[j + b[k]] % MOD; } } const auto nxt = ntt.multiply(dp, ways); copy(next(nxt.begin(), -lb), next(nxt.begin(), -lb + M * m * 2 + 1), dp.begin()); } cout << dp[M * m] << '\n'; // ModInt ans = 0; // const auto f = [&](auto&& f, vector& c, vector& d, ModInt ways) -> void { // if (c.size() < n) { // const int i = c.size(); // for (int j = 0; j <= a[i]; ++j) { // c.emplace_back(j); // f(f, c, d, ways * ModInt::nCk(a[i], j)); // c.pop_back(); // } // } else if (d.size() < n) { // const int i = d.size(); // for (int j = 0; j <= b[i]; ++j) { // d.emplace_back(j); // f(f, c, d, ways * ModInt::nCk(b[i], j)); // d.pop_back(); // } // } else { // REP(i, n - m + 1) { // int c_sum = 0, d_sum = 0; // REP(j, m) c_sum += c[i + j]; // REP(j, m) d_sum += d[i + j]; // if (c_sum != d_sum) return; // } // ans += ways; // } // }; // vector c, d; // c.reserve(n); // d.reserve(n); // f(f, c, d, 1); // assert(dp[0] == ans); return 0; }