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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#340174 | #1810. Generate the Sequences | HKOI0# | RE | 0ms | 0kb | C++20 | 2.1kb | 2024-02-28 17:32:23 | 2024-02-28 17:32:23 |
answer
#include <bits/stdc++.h>
#define int long long
using namespace std;
using ll = long long;
const int N = 2e6 + 11;
const int MOD = 998244353;
int fa[N], fi[N];
int pm(int a, int b){
if (b == 0) return 1;
return pm(a * a % MOD, b / 2) * (b % 2 ? a : 1) % MOD;
}
int mi(int a){
return pm(a, MOD - 2);
}
int binom(int n, int r){
return fa[n] * fi[r] % MOD * fi[n - r] % MOD;
}
template<int MOD = 998244353>
struct Mint{
int value;
Mint() : value(0) {};
Mint(int value) : value(value) { value = (value % MOD + MOD) % MOD; };
Mint operator+ (const Mint& o) const { int res = value + o.value; return res >= MOD ? res - MOD : res; }
Mint operator+= (const Mint& o) { *this = *this + o; }
Mint operator- (const Mint& o) const { int res = value - o.value; return res < 0 ? res + MOD : res; }
Mint operator* (const Mint& o) const { int res = value * o.value % MOD; return res; }
Mint operator/ (const Mint& o) const { return *this * o.inv(); }
Mint inv() const { return mi(value); }
friend ostream& operator<< (ostream& out, const Mint& m) {
return cout << m.value;
}
};
using Zn = Mint<MOD>;
void solve() {
int n,m;
cin>>n>>m;
vector dp(n+2,vector<Zn>(n+2));
dp[0][0] = 1;
for(int i = 0; i < n; i++) {
for (int j = 0; j <= i; j++) {
dp[i + 1][j + 1] += dp[i][j];
if (i - j < j * (m - 2)) {
dp[i + 1][j] += dp[i][j] * (Zn(j) * Zn(m - 2) - Zn(i - j));
}
}
}
Zn ans = 0;
for(int i = 0; i <= n; i++) {
Zn sum = 0;
for (int j = 0; j <= i; j++) {
sum += dp[i][j];
}
ans += sum * Zn(binom(n,i));
}
cout << ans << '\n';
}
int32_t main() {
#ifndef LOCAL
ios::sync_with_stdio(false);
cin.tie(nullptr);
#endif
fa[0] = 1; for (int i = 1; i < N; i++) fa[i] = fa[i - 1] * i % MOD;
fi[N - 1] = mi(fa[N - 1]); for (int i = N - 2; i >= 0; i--) fi[i] = fi[i + 1] * (i + 1) % MOD;
int T = 1;
// cin >> T;
while (T--) solve();
return 0;
}
詳細信息
Test #1:
score: 0
Runtime Error
input:
2 3