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1726E-E-AlmostPerfect.cpp
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1726E-E-AlmostPerfect.cpp
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//url:https://codeforces.com/contest/1726/problem/E
//time:2022-09-06 18:04:01
//name:E-AlmostPerfect
#include <bits/stdc++.h>
using i64 = long long;
constexpr int P = 998244353;
using i64 = long long;
// assume -P <= x < 2P
int norm(int x) {
if (x < 0) {
x += P;
}
if (x >= P) {
x -= P;
}
return x;
}
template<class T>
T power(T a, i64 b) {
T res = 1;
for (; b; b /= 2, a *= a) {
if (b % 2) {
res *= a;
}
}
return res;
}
struct Z {
int x;
Z(int x = 0) : x(norm(x)) {}
Z(i64 x) : x(norm(x % P)) {}
int val() const {
return x;
}
Z operator-() const {
return Z(norm(P - x));
}
Z inv() const {
assert(x != 0);
return power(*this, P - 2);
}
Z &operator*=(const Z &rhs) {
x = i64(x) * rhs.x % P;
return *this;
}
Z &operator+=(const Z &rhs) {
x = norm(x + rhs.x);
return *this;
}
Z &operator-=(const Z &rhs) {
x = norm(x - rhs.x);
return *this;
}
Z &operator/=(const Z &rhs) {
return *this *= rhs.inv();
}
friend Z operator*(const Z &lhs, const Z &rhs) {
Z res = lhs;
res *= rhs;
return res;
}
friend Z operator+(const Z &lhs, const Z &rhs) {
Z res = lhs;
res += rhs;
return res;
}
friend Z operator-(const Z &lhs, const Z &rhs) {
Z res = lhs;
res -= rhs;
return res;
}
friend Z operator/(const Z &lhs, const Z &rhs) {
Z res = lhs;
res /= rhs;
return res;
}
friend std::istream &operator>>(std::istream &is, Z &a) {
i64 v;
is >> v;
a = Z(v);
return is;
}
friend std::ostream &operator<<(std::ostream &os, const Z &a) {
return os << a.val();
}
};
void solve() {
int n;
std::cin >> n;
std::vector<Z> fac(n + 1), invfac(n + 1);
fac[0] = 1;
for (int i = 1; i <= n; i++) {
fac[i] = fac[i - 1] * i;
}
invfac[n] = fac[n].inv();
for (int i = n; i; i--) {
invfac[i - 1] = invfac[i] * i;
}
std::vector<Z> f(n + 1);
f[0] = 1;
for (int i = 1; i <= n; i++) {
f[i] = f[i - 1];
if (i > 1) {
f[i] += (i - 1) * f[i - 2];
}
}
Z ans = 0;
for (int k = 0; 4 * k <= n; k++) {
ans += fac[n - 2 * k] * invfac[n - 4 * k] * f[n - 4 * k] * invfac[k];
}
std::cout << ans << "\n";
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int t;
std::cin >> t;
while (t--) {
solve();
}
return 0;
}