Submission #17268751

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define int long long
void read (int &x) {
    char ch = getchar(); x = 0;
    while (!isdigit(ch)) ch = getchar();
    while (isdigit(ch)) x = x * 10 + ch - 48, ch = getchar();
} const int N = 4010, mod = 998244353;
int n, k, pw[N], in[N], p[N];
int qpow (int x, int y) {
    int t = 1;
    while (y) {
        if (y & 1) t = t * x % mod;
        x = x * x % mod, y >>= 1;
    } return t;
}
int C (int x, int y) {
    return pw[x] * in[y] % mod * in[x - y] % mod;
}
signed main() {
    read (k), read (n);
    pw[0] = p[0] = 1;
    for (int i = 1; i < N; ++i)
        pw[i] = pw[i - 1] * i % mod, p[i] = p[i - 1] * 2 % mod;
    in[N - 1] = qpow (pw[N - 1], mod - 2);
    for (int i = N - 2; i >= 0; --i)
        in[i] = in[i + 1] * (i + 1) % mod;
    // for (int i = 0; i <= 10; ++i) printf ("%lld ", in[i]); puts ("");
    for (int i = 2; i <= k * 2; ++i) {
        int num = k - i + 1, res = 0;
        int tmp = i / 2 - (i % 2 == 0);
        if (i > k) {
            tmp = (k + k - i + 1) / 2;
            num = i - k - 1;
        }
        // printf ("%d %d\n", num, tmp);
        for (int j = 0; j <= tmp; ++j) {
            if (n >= j) res = (res + C (tmp, j) * C (n + num - 1, n - j) % mod * p[j]) % mod;
            if (i % 2 == 0 && n > j)
                res = (res + C (tmp, j) * C (n + num - 2, n - j - 1) % mod * p[j]) % mod;
        }
        printf ("%lld\n", res);
    }
    return 0;
}

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