text
stringlengths
49
983k
#include <bits/stdc++.h> #pragma comment(linker, "/STACK:1024000000,1024000000") using namespace std; int n, w, b, c[4005][4005], fac[4005]; int main() { ios::sync_with_stdio(false); cin.tie(0); cin >> n >> w >> b; c[0][0] = 1; for (int i = 1; i <= 4000; i++) { c[i][0] = 1; for (int j = 1; j <= i; j++) { c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % 1000000009; } } fac[0] = 1; for (int i = 1; i <= 4000; i++) { fac[i] = (1ll * fac[i - 1] * i) % 1000000009; } long long ans = 0; for (int i = 2; i <= n - 1; i++) { for (int j = i; j <= n - 1; j++) { int bd = j - i + 1, wd = n - bd; ans = (ans + (1ll * fac[b] * c[b - 1][bd - 1] % 1000000009) * (1ll * fac[w] * c[w - 1][wd - 1] % 1000000009) % 1000000009) % 1000000009; } } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 4003, P = 1e9 + 9; int n, w, b, jc[N << 1]; inline void in(register int &x) { int f = 0; x = 0; char c = getchar(); while (c < '0' || c > '9') f |= c == '-', c = getchar(); while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x = f ? -x : x; } inline int mi(register int x, register int k) { register int s = 1; while (k) { if (k & 1) s = (long long)s * x % P; x = (long long)x * x % P, k >>= 1; } return s; } inline int inv(register int x) { return x == 0 ? 1 : mi(x, P - 2); } inline int C(register int m, register int n) { return (long long)jc[n] * inv(jc[n - m]) % P * inv(jc[m]) % P; } int main() { in(n), in(w), in(b), jc[0] = 1; for (register int i = 1; i <= w + b; ++i) jc[i] = (long long)jc[i - 1] * i % P; printf("%d\n", (long long)C(n - 3, w + b - 3) * (w - 1) % P * jc[w] % P * jc[b] % P); }
#include <bits/stdc++.h> using namespace std; long long n, w, t; long long ans = 1, mod = (long long)1e9 + 9; long long cnt = 0; long long pow(long long a, long long b) { if (b == 0) return 1; long long s = pow(a, b / 2); s *= s; s %= mod; if (b & 1) s *= a; s %= mod; return s; } long long c(long long a, long long b) { long long s = 1; for (long long i = 0; i < b; i++) s = (s * (a - i)) % mod; for (long long i = 1; i <= b; i++) s = (s * pow(i, mod - 2)) % mod; return s; } int main() { scanf("%I64d%I64d%I64d", &n, &w, &t); for (long long i = 1; i <= w; i++) { ans *= i; ans %= mod; } for (long long i = 1; i <= t; i++) { ans *= i; ans %= mod; } ans *= (w - 1); ans %= mod; ans *= c(t + w - 3, n - 3); ans %= mod; printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 4003, P = 1e9 + 9; int n, w, b, jc[N << 1]; inline void in(register int &x) { int f = 0; x = 0; char c = getchar(); while (c < '0' || c > '9') f |= c == '-', c = getchar(); while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x = f ? -x : x; } inline int mi(register int x, register int k) { register int s = 1; while (k) { if (k & 1) s = (long long)s * x % P; x = (long long)x * x % P, k >>= 1; } return s; } inline int inv(register int x) { return mi(x, P - 2); } inline int C(register int m, register int n) { return (long long)jc[n] * inv(jc[n - m]) % P * inv(jc[m]) % P; } int main() { in(n), in(w), in(b), jc[0] = 1; for (register int i = 1; i <= w + b; ++i) jc[i] = (long long)jc[i - 1] * i % P; printf("%d\n", (long long)C(n - 3, w + b - 3) * (w - 1) % P * jc[w] % P * jc[b] % P); }
#include <bits/stdc++.h> using namespace std; const int oo = INT_MAX >> 1; const int Mo = 1000000009; long long C[4100][4100]; long long fac[4100]; int main() { int i, j; fac[0] = C[0][0] = 1; for (i = 1; i <= 4000; i++) { fac[i] = fac[i - 1] * i % Mo; C[i][0] = 1; for (j = 1; j <= i; j++) C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % Mo; } int N, w, b; cin >> N >> w >> b; long long ans = 0; int l = max(1, N - w), r = min(b, N); for (i = l; i <= r; i++) ans = (ans + C[b - 1][i - 1] * fac[b] % Mo * C[w - 1][N - i - 1] % Mo * fac[w] % Mo * (N - i - 1) % Mo) % Mo; cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; int n, w, b; long long fact[4096], inv[4096]; long long quick_pow(long long a, int k) { int ans = 1; while (k > 0) { if (k & 1) ans = (ans * a) % 1000000009; k >>= 1; a = (a * a) % 1000000009; } return ans % 1000000009; } void init() { fact[0] = 1; inv[0] = 1; for (int i = 1; i < 4096; i++) { fact[i] = fact[i - 1] * i % 1000000009; inv[i] = quick_pow(fact[i], 1000000009 - 2); } } long long C(int M, int N) { if (M > N) return 0; return inv[M] * fact[N] % 1000000009 * inv[N - M] % 1000000009; } void work() { long long ans = 0; for (int i = 2; i < n; i++) { for (int j = i; j < n; j++) { int x = C(j - i, b - 1), y = C(n - (j - i + 1) - 1, w - 1); ; ; ans = (ans + C(j - i, b - 1) * C(n - (j - i + 1) - 1, w - 1) % 1000000009) % 1000000009; } } cout << ans * fact[w] % 1000000009 * fact[b] % 1000000009 << endl; } int main() { ios::sync_with_stdio(false); cin >> n >> w >> b; init(); work(); return 0; }
#include <bits/stdc++.h> using namespace std; int C[4010][4010]; long long mi[4010]; const int mod = 1000000009; void init() { int i, j; C[0][0] = 1; for (i = 1; i <= 4000; i++) { C[i][0] = C[i][i] = 1; for (j = 1; j < i; j++) { C[i][j] = C[i - 1][j] + C[i - 1][j - 1]; if (C[i][j] >= mod) C[i][j] -= mod; } } } int main() { int n, w, b, i, j, k, m; for (i = 1, mi[0] = 1; i <= 4000; i++) mi[i] = mi[i - 1] * i % mod; init(); scanf("%d%d%d", &n, &m, &b); int ans = 0; long long t; for (i = 1; i + 2 <= n; i++) { t = C[b - 1][i - 1]; t *= mi[b], t %= mod; t *= n - i - 1; t %= mod; t *= C[m - 1][n - i - 1], t %= mod; t *= mi[m], t %= mod; ans += t, ans %= mod; } cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; int Read() { char c; while (c = getchar(), (c != '-') && (c < '0' || c > '9')) ; bool neg = (c == '-'); int ret = (neg ? 0 : c - 48); while (c = getchar(), c >= '0' && c <= '9') ret = ret * 10 + c - 48; return neg ? -ret : ret; } const int MOD = 9 + 1e9; int N, W, B; int Pow(int x, int y) { if (y == 1) return x; int tmp = Pow(x, y >> 1); tmp = (long long)tmp * tmp % MOD; return y & 1 ? (long long)tmp * x % MOD : tmp; } long long fac(int n) { long long ret = 1; for (int i = 2; i <= n; i++) (ret *= i) %= MOD; return ret; } long long C(int n, int m) { return fac(n) * Pow(fac(m), MOD - 2) % MOD * Pow(fac(n - m), MOD - 2) % MOD; } int main() { scanf("%d%d%d", &N, &W, &B); printf("%d\n", fac(W) * fac(B) % MOD * (W - 1) % MOD * C(W + B - 3, N - 3) % MOD); return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 4005; const long long mod = 1000000009; int n, w, b; long long f[MAXN][MAXN], C[MAXN][MAXN]; int main() { scanf("%d %d %d", &n, &w, &b); f[0][0] = 1; for (int i = 0; i <= 4000; i++) C[i][0] = 1; for (int i = 1; i <= 4000; i++) for (int j = 1; j <= 4000; j++) C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % mod; long long ans = 0; for (int i = 1; i <= n; i++) for (int j = i + 2; j <= n; j++) if (i + (1 + n - j) <= w && j - i - 1 <= b) { int x = i + n - j + 1, y = n - x; ans += C[w - 1][x - 1] * C[b - 1][y - 1] % mod; ans %= mod; } for (int i = 1; i <= w; i++) ans = ans * i % mod; for (int i = 1; i <= b; i++) ans = ans * i % mod; printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long ch[4010][4010]; long long ans, jc[4010]; long long p; int n, a, b, i, j, c; int main() { scanf("%d%d%d", &n, &a, &b); for (i = 0; i <= 4000; i++) ch[i][0] = 1; for (i = 1; i <= max(a, b); i++) for (j = 1; j <= max(a, b); j++) ch[i][j] = (ch[i - 1][j - 1] + ch[i - 1][j]) % 1000000009ll; jc[1] = 1; for (i = 1; i <= 4000; i++) jc[i + 1] = (jc[i] * (i + 1)) % 1000000009ll; for (i = 1; i <= b; i++) { if (n - i < 2 || n - i > a) continue; c = n - i; p = jc[b] * ch[b - 1][i - 1] % 1000000009; p = p * jc[a] % 1000000009; p = p * ch[a - 1][c - 1] % 1000000009; p = p * ch[c - 1][1] % 1000000009; ans = ans + p; ans %= 1000000009; } cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const int modd = 1e9 + 9; const int maxn = 4000 + 15; long long C[maxn][maxn]; int n, w, b; int main() { scanf("%d%d%d", &n, &w, &b); long long jc = 1ll; for (int i = 2; i <= w; i++) jc = jc * i % modd; for (int i = 2; i <= b; i++) jc = jc * i % modd; long long ans = 0; for (int i = 0, j; i <= max(w, b); i++) for (C[i][0] = j = 1; j <= i; j++) C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % modd; for (int i = 2; i < n; i++) if (w >= i && b >= n - i) ans += C[w - 1][i - 1] * C[b - 1][n - i - 1] % modd * (i - 1) % modd; ans %= modd; ans = ans * jc % modd; printf("%d\n", (int)ans); return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1000000009; int n, b, w; long long c[4010][4010]; long long ans; void init() { int sz = max(max(n, b), w); c[0][0] = 1; for (int i = 1; i <= sz; i++) { c[i][0] = c[i][i] = 1; for (int j = 1; j < i; j++) { c[i][j] = c[i - 1][j] + c[i - 1][j - 1]; if (c[i][j] >= mod) c[i][j] -= mod; } } } long long frac(int x) { long long res = 1; for (int i = 2; i <= x; i++) res = res * i % mod; return res; } int main() { cin >> n >> w >> b; init(); for (int i = 2; i <= n; i++) { for (int j = i; j < n; j++) { ans += c[b - 1][j - i] * c[w - 1][n - j + i - 2] % mod; if (ans >= mod) ans -= mod; } } ans = ans * frac(b) % mod * frac(w) % mod; cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; inline long long san(long long x) { if (x < 0) x = (x % 1000000009) + 1000000009; if (x >= 1000000009) x %= 1000000009; return x; } long long P[4001]; int C[2 * 4001][4001][2]; int main() { int N, W, B; scanf("%d %d %d", &N, &W, &B); P[0] = 1; for (int i = 1; i < 4001; i++) P[i] = san(P[i - 1] * i); memset(C, 0, sizeof C); C[0][0][0] = C[0][0][1] = 1; for (int i = 1; i < 2 * 4001 - 1; i++) { C[i][0][0] = 1; C[i][0][1] = 1 + C[i - 1][0][1]; for (int j = 1; 2 * j < i; j++) { for (int k = 0; k < 2; k++) { if (k) C[i][j][k] = san(C[i][j][0] + C[i - 1][j][1]); else if (i - 2 >= 0) C[i][j][k] = san(C[i - 2][j - 1][1] - C[0][j - 1][1]); } } } int w; long long ans = 0; for (int b = max(1, N - W); b <= B and b <= N - 2; b++) { w = N - b; ans = san(ans + san((long long)C[W + w - 1][w - 1][0] * C[B + b - 1][b - 1][0]) * (w - 1)); } ans = san(ans * san(P[W] * P[B])); printf("%d\n", (int)ans); }
#include <bits/stdc++.h> using namespace std; int n, W, B; long long b[4005], f[4005][4005], ans = 0; long long mo(long long a) { if (a >= 0 && a < 1000000009) return a; a %= 1000000009; if (a < 0) a += 1000000009; return a; } long long cal(int n, int m) { return f[m][n]; } int main() { scanf("%d%d%d", &n, &W, &B); b[0] = 1; for (int i = 1; i <= max(W, B); i++) b[i] = mo(b[i - 1] * i); for (int i = 1; i <= max(W, B); i++) { f[i][1] = b[i]; for (int j = 2; j <= n; j++) f[i][j] = mo(f[i - 1][j] * (i - 1 + j) + f[i - 1][j - 1] * j); } for (int i = 1; i <= n; i++) for (int j = 1; j + i < n; j++) if (W >= i + j && B >= n - i - j) ans = mo(ans + cal(i + j, W) * cal(n - i - j, B)); cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int m[5000][5000]; char v[5000][5000]; long long int force(int p, int t) { if (p == 0 && t == 0) return 1; if (p == 0 || t == 0) return 0; if (p > t) return 0; if (v[p][t]) return m[p][t]; long long int s = 0; s += t * force(p - 1, t - 1); s %= 1000000009; s += t * force(p, t - 1); s %= 1000000009; v[p][t] = 1; m[p][t] = s; return s; } int main() { long long int s = 0; int n, w, b; cin >> n >> w >> b; for (int i = 2; i <= n - 1; i++) { for (int j = i; j <= n - 1; j++) { long long int u = 1; u *= force(i - 1 + n - j, w); u %= 1000000009; u *= force(j - i + 1, b); u %= 1000000009; s += u; s %= 1000000009; } } cout << s << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int MAX = 4010; const int MOD = 1e9 + 9; long long f[MAX], finv[MAX], inv[MAX]; void init() { f[0] = inv[0] = inv[1] = finv[0] = finv[1] = f[1] = 1; for (int i = 2; i < MAX; ++i) { f[i] = f[i - 1] * i % MOD; inv[i] = (MOD - MOD / i) * inv[MOD % i] % MOD; finv[i] = finv[i - 1] * inv[i] % MOD; } } long long C(int n, int m) { if (m < 0 || m > n) return 0; return f[n] * finv[n - m] % MOD * finv[m] % MOD; } int main(void) { init(); int n, w, b; scanf("%d%d%d", &n, &w, &b); long long ans = 0; for (int i = 1; i <= b && i <= n - 2; ++i) { ans = (ans + C(b - 1, i - 1) * f[b] % MOD * C(w - 1, n - i - 1) % MOD * f[w] % MOD * (n - i - 1) % MOD) % MOD; } printf("%lld\n", (ans % MOD + MOD) % MOD); return 0; }
#include <bits/stdc++.h> using namespace std; int n, w, b; int fac[4044], c[4044][4044]; struct modular_arithmetic { int mod; modular_arithmetic() { mod = 1000000009; } int add(int x, int y) { return (x += y) < mod ? x : x - mod; } int mul(int x, int y) { return (int)((long long int)x * y % mod); } }; modular_arithmetic ma; int f(int n, int m) { return ma.mul(fac[m], c[m - 1][n - 1]); } int main() { scanf("%d%d%d", &n, &w, &b); int lim = max(w, b); fac[0] = fac[1] = 1; for (int i = 2; i <= lim; i++) fac[i] = ma.mul(fac[i - 1], i); for (int i = 0; i <= lim; i++) { c[i][0] = c[i][i] = 1; for (int j = 1; j < i; j++) c[i][j] = ma.add(c[i - 1][j], c[i - 1][j - 1]); } int ans = 0; for (int lb = max(1, n - w); lb <= min(n - 2, b); lb++) { int cb = 0; cb = ma.add(cb, f(lb, b)); int cw = 0; cw = ma.add(cw, f(n - lb, w)); cw = ma.mul(cw, n - lb - 1); ans = ma.add(ans, ma.mul(cb, cw)); } printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 1e4, mod = 1e9 + 9; int fact[maxn], prv[maxn]; int power(int a, int b) { if (b == 0) return 1; int t = power(a, b >> 1); t = (1LL * t * t) % mod; if (b & 1) t = (1LL * t * a) % mod; return t; } int C(int n, int r) { if (r < 0 || r > n) return 0; int ret = (1LL * prv[r] * prv[n - r]) % mod; ret = (1LL * ret * fact[n]) % mod; return ret; } int main() { fact[0] = 1; for (int i = 1; i < maxn; i++) fact[i] = (1LL * i * fact[i - 1]) % mod; for (int i = 0; i < maxn; i++) prv[i] = power(fact[i], mod - 2); int n, w, b; cin >> n >> w >> b; int ans = (1LL * (w - 1) * C(w + b - 3, n - 3)) % mod; ans = (1LL * ans * fact[w]) % mod; ans = (1LL * ans * fact[b]) % mod; cout << ans << '\n'; return 0; }
#include <bits/stdc++.h> const int N = 4005, mo = (int)1e9 + 9; int n, a, b, ans; int C[N][N]; int calc(int n, int m) { if (n < m) return 0; return C[n - 1][m - 1]; } int main() { scanf("%d%d%d", &n, &a, &b); for (int i = 0; i <= a || i <= b; i++) for (int j = 0; j <= i; j++) C[i][j] = j ? (C[i - 1][j - 1] + C[i - 1][j]) % mo : 1; for (int i = 1; i < n; i++) for (int j = i + 1; j < n; j++) ans = (ans + 1LL * calc(a, n - (j - i)) * calc(b, j - i)) % mo; for (int i = 1; i <= a; i++) ans = 1LL * ans * i % mo; for (int i = 1; i <= b; i++) ans = 1LL * ans * i % mo; printf("%d\n", ans); }
#include <bits/stdc++.h> const int maxn = 4e3 + 10; const int mod = 1e9 + 9; int n, a, b, ans, fac[maxn], inv[maxn]; inline int power(int x, int y) { int ans = 1; for (; y; y >>= 1, x = 1ll * x * x % mod) if (y & 1) ans = 1ll * ans * x % mod; return ans; } inline int C(int n, int m) { if (n == 0 && m == 0) return 1; if (n < m) return 0; return 1ll * fac[n] * inv[m] % mod * inv[n - m] % mod; } int main() { fac[0] = inv[0] = 1; for (int i = 1; i < maxn; i++) { fac[i] = 1ll * fac[i - 1] * i % mod; inv[i] = power(fac[i], mod - 2); } scanf("%d%d%d", &n, &a, &b); for (int i = 2; i <= n; i++) for (int j = i; j < n; j++) (ans += 1ll * C(b - 1, j - i) * C(a - 1, n - j + i - 2) % mod * fac[a] % mod * fac[b] % mod) %= mod; printf("%d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = 0x20202020; const int mod = 1000000009; template <class T> inline void read(T& x) { bool fu = 0; char c; for (c = getchar(); c <= 32; c = getchar()) ; if (c == '-') fu = 1, c = getchar(); for (x = 0; c > 32; c = getchar()) x = x * 10 + c - '0'; if (fu) x = -x; }; template <class T> inline void read(T& x, T& y) { read(x); read(y); } template <class T> inline void read(T& x, T& y, T& z) { read(x); read(y); read(z); } template <class T> inline void read(T& x, T& y, T& z, T& q) { read(x); read(y); read(z); read(q); } const int DX[] = {1, 0, -1, 0}, DY[] = {0, 1, 0, -1}; long long powmod(long long a, long long b) { long long res = 1; a %= mod; for (; b; b >>= 1) { if (b & 1) res = res * a % mod; a = a * a % mod; } return res; } long long powmod(long long a, long long b, long long mod) { long long res = 1; a %= mod; for (; b; b >>= 1) { if (b & 1) res = res * a % mod; a = a * a % mod; } return res; } long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; } const int N = 4444, M = 4000; int l, m, n, t, C[N][N]; int main() { scanf("%d%d%d", &n, &m, &l); for (int _tmp = M, i = 0; i <= _tmp; ++i) C[i][0] = 1; for (int _tmp = M, i = 1; i <= _tmp; ++i) for (int _tmp = i, j = 1; j <= _tmp; ++j) C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % mod; long long ans = 0; for (int _tmp = n - 1, i = 1; i <= _tmp; ++i) for (int _tmp = n - 1, j = i + 1; j <= _tmp; ++j) { ans = (ans + 1ll * C[l - 1][j - i - 1] * C[m - 1][(n - (j - i)) - 1]) % mod; } for (int _tmp = m, i = 1; i <= _tmp; ++i) ans = (ans * i) % mod; for (int _tmp = l, i = 1; i <= _tmp; ++i) ans = (ans * i) % mod; printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int M = 4005, P = (int)1e9 + 9; void Add(int &x, int y) { x += y; if (x >= P) x -= P; } int fast(int x, int p) { int re = 1; while (p) { if (p & 1) re = (long long)re * x % P; x = (long long)x * x % P, p >>= 1; } return re; } int n, a, b; int fac[M * 3], rfac[M * 3]; int C(int a, int b) { if (a < b) return 0; return (long long)fac[a] * rfac[b] % P * rfac[a - b] % P; } int main() { fac[0] = 1; for (int i = 1; i < M * 3; i++) fac[i] = (long long)fac[i - 1] * i % P; rfac[M * 3 - 1] = fast(fac[M * 3 - 1], P - 2); for (int i = M * 3 - 2; i >= 0; i--) rfac[i] = (long long)rfac[i + 1] * (i + 1) % P; scanf("%d %d %d", &n, &a, &b); int ans = 0; for (int i = 1, up = min(n - 2, b); i <= up; i++) Add(ans, (long long)(n - i - 1) * C(b - 1, i - 1) % P * C(a - 1, n - i - 1) % P); ans = (long long)ans * fac[a] % P * fac[b] % P; printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long ans, dp[4001][4001], n, w, b, hehe; int main() { cin >> n >> w >> b; for (int i = 0; i <= max(w, b); i++) dp[0][i] = 1; for (int i = 1; i <= n; i++) for (int j = 1; j <= max(w, b); j++) dp[i][j] = (dp[i][j - 1] + dp[i - 1][j - 1]) % 1000000009; for (int i = 1; i <= n - 2; i++) ans = (ans + (dp[i][b] - dp[i][b - 1] + 1000000009) % 1000000009 * (dp[n - i][w] - dp[n - i][w - 1] + 1000000009) % 1000000009 * (n - i - 1) % 1000000009) % 1000000009; for (int i = 1; i <= w; i++) ans = ans * i % 1000000009; for (int i = 1; i <= b; i++) ans = ans * i % 1000000009; cout << ans << endl; return 0; }
#include <bits/stdc++.h> #pragma comment(linker, "/STACK:16777216") using namespace std; const double eps = 1e-9; const double pi = acos(-1.0); const int mod = (int)1e9 + 9; const int maxn = 4004; int A[maxn], B[maxn], C[2 * maxn][2 * maxn], dp1[maxn], dp2[maxn]; int main() { for (int i = 0; i < 2 * maxn; i++) { C[i][0] = 1; } for (int i = 1; i < 2 * maxn; i++) { for (int j = 1; j <= i; j++) { C[i][j] = C[i - 1][j] + C[i - 1][j - 1]; C[i][j] %= mod; } } int n, w, b; cin >> n >> w >> b; A[1] = w; for (int i = 2; i <= w; i++) { A[i] = A[i - 1] * (long long)(w - i + 1) % mod; } B[1] = b; for (int i = 2; i <= b; i++) { B[i] = B[i - 1] * (long long)(b - i + 1) % mod; } for (int i = 1; i <= w; i++) { dp1[i] += C[w - 1][i - 1] * (long long)A[w] % mod; dp1[i] %= mod; } for (int i = 1; i <= b; i++) { dp2[i] += C[b - 1][i - 1] * (long long)B[b] % mod; dp2[i] %= mod; } int res = 0; for (int i = 2; i < n; i++) { if (i <= w && n - i <= b) { res += dp1[i] * (long long)dp2[n - i] % mod * (long long)(i - 1) % mod; res %= mod; } } cout << res << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 4003, P = 1e9 + 9; int n, w, b, jc[N << 1]; inline void in(register int &x) { int f = 0; x = 0; char c = getchar(); while (c < '0' || c > '9') f |= c == '-', c = getchar(); while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x = f ? -x : x; } inline int mi(register int x, register int k) { register int s = 1; while (k) { if (k & 1) s = (long long)s * x % P; x = (long long)x * x % P, k >>= 1; } return s; } inline int inv(register int x) { return x == 0 ? 1 : mi(x, P - 2); } inline int C(register int m, register int n) { return (long long)jc[n] * inv(jc[n - m]) % P * inv(jc[m]) % P; } int main() { in(n), in(w), in(b), jc[0] = 1; for (register int i = 1; i <= w + b; ++i) jc[i] = (long long)jc[i - 1] * i % P; printf("%d\n", (long long)C(n - 3, w + b - 3) * (w - 1) % P * jc[w] % P * jc[b] % P); }
#include <bits/stdc++.h> using namespace std; const int MAXN = 4000 + 10, MOD = (int)1e9 + 9; int n, m, b, w, f[MAXN][MAXN]; int main() { cin >> n >> w >> b; m = max(b, w); f[0][0] = 1; for (int i = 1; i <= m; ++i) { for (int j = 1; j <= i; ++j) f[i][j] = ((long long)f[i - 1][j] * (j + i - 1) + (long long)f[i - 1][j - 1] * j) % MOD; } int Tohka = 0; for (int i = 1; i <= min(b, n - 2); ++i) Tohka = ((long long)Tohka + (long long)f[w][n - i] * f[b][i] % MOD * (n - i - 1)) % MOD; cout << Tohka << endl; fclose(stdin); fclose(stdout); return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 4010, mod = 1e9 + 9; long long fact[maxn], C[maxn][maxn]; void init(long long n) { for (int i = 0; i <= n; i++) { C[i][0] = 1; } for (int i = 1; i <= n; i++) { for (int j = 1; j <= i; j++) { C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % mod; } } fact[0] = 1; for (long long i = 1; i <= n; i++) { fact[i] = (fact[i - 1] * i) % mod; } } int main() { long long n, w, b; cin >> n >> w >> b; init(max(n, max(b, w))); long long res = 0; for (long long i = 1; i <= b; i++) { long long add = n - i - 1; if (add == 0) break; add = (add * C[b - 1][i - 1]) % mod; add = (add * fact[b]) % mod; add = (add * C[w - 1][n - i - 1]) % mod; add = (add * fact[w]) % mod; res = (res + add) % mod; } cout << res << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int md = 1e9 + 9; long long ans = 0; long long f[4444][4444], fact[4444]; int good, bad, i, n, j; int main() { scanf("%d %d %d", &n, &good, &bad); int t = max(max(good, bad), n); for (i = 0; i <= t; i++) f[i][0] = 1; for (i = 1; i <= t; i++) for (j = 1; j <= i; j++) f[i][j] = (f[i - 1][j - 1] + f[i - 1][j]) % md; fact[0] = 1; for (i = 1; i <= t; i++) fact[i] = fact[i - 1] * i % md; for (j = 1; j <= good; j++) { for (i = 1; i <= bad; i++) { if (n - i > good || i + j >= n) continue; ans += f[good - 1][n - i - 1] * fact[good] % md * f[bad - 1][i - 1] % md * fact[bad]; ans = ans % md; } } printf("%I64d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int MaxN = 4005; const int M = 1000000009; int n, u, v; int binom[MaxN][MaxN]; int main() { cin >> n >> u >> v; for (int i = 0; i <= max(max(u, v), n); ++i) { binom[i][0] = 1; for (int j = 1; j <= i; ++j) { binom[i][j] = binom[i - 1][j] + binom[i - 1][j - 1]; if (binom[i][j] >= M) binom[i][j] -= M; } } int res = 0; for (int i = 1; i <= n - 2; ++i) for (int j = i + 1; j <= n - 1; ++j) res = (res + (long long)binom[v - 1][j - i - 1] * binom[u - 1][n - j + i - 1]) % M; for (int i = 2; i <= u; ++i) res = (long long)res * i % M; for (int i = 2; i <= v; ++i) res = (long long)res * i % M; cout << res << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1000000009; int n, w, b; long long fac[8005], inv[8005]; inline void pre() { fac[0] = fac[1] = inv[0] = inv[1] = 1; for (int i = 2; i <= 8000; i++) fac[i] = fac[i - 1] * i % mod; for (int i = 2; i <= 8000; i++) inv[i] = (mod - mod / i) * inv[mod % i] % mod; for (int i = 2; i <= 8000; i++) inv[i] = inv[i - 1] * inv[i] % mod; } int C(int n, int m) { return fac[n] * inv[m] % mod * inv[n - m] % mod; } int main() { pre(); scanf("%d%d%d", &n, &w, &b); cout << fac[w] * fac[b] % mod * (w - 1) % mod * C(w + b - 3, n - 3) % mod << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int fact[4010], invfact[4010]; int Power(int p, int n) { int ans = 1; for (; n; n >>= 1, p = (long long)p * p % 1000000009) if (n & 1) ans = (long long)ans * p % 1000000009; return ans; } int C(int n, int m) { if (n < m) return 0; return (long long)fact[n] * invfact[m] % 1000000009 * invfact[n - m] % 1000000009; } int n, w, b; int work() { fact[0] = 1, invfact[0] = 1; int N = max(max(w, b), n); for (int i = 1; i <= N; ++i) fact[i] = (long long)fact[i - 1] * i % 1000000009, invfact[i] = Power(fact[i], 1000000009 - 2); int ans = 0; for (int i = 2; i < n; ++i) for (int j = i; j < n; ++j) ans = (ans + (long long)C(b - 1, j - i) * C(w - 1, n - (j - i + 1) - 1)) % 1000000009; return (long long)ans * fact[w] % 1000000009 * fact[b] % 1000000009; } int main() { scanf("%d %d %d", &n, &w, &b); printf("%d\n", work()); return 0; }
#include <bits/stdc++.h> using namespace std; template <typename T> inline void read(T& x) { x = 0; char c; int sign = 1; do { c = getchar(); if (c == '-') sign = -1; } while (!isdigit(c)); do { x = x * 10 + c - '0'; c = getchar(); } while (isdigit(c)); x *= sign; } long long n, w, b, ans; long long fac[5010], c[5010][5010]; long long comb(long long n, long long m) { if (c[n][m] > 0) return c[n][m]; if (m == 0) return c[n][m] = 1; if (n >= m + 1) return c[n][m] = (comb(n - 1, m) + comb(n - 1, m - 1)) % 1000000009; else return c[n][m] = comb(n - 1, m - 1); } int main() { read(n), read(w), read(b); fac[0] = 1; for (long long i = 1; i <= max(w, b); i++) fac[i] = (fac[i - 1] * i) % 1000000009; for (long long i = max(n - w, 1ll); i <= min(n - 2, b); i++) { long long k = comb(b - 1, i - 1) * fac[b] % 1000000009; k = k * fac[w] % 1000000009 * comb(w - 1, n - i - 1) % 1000000009 * (n - i - 1) % 1000000009; ans = (ans + k) % 1000000009; } printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1e9 + 9; const int mxn = 4005; int n, w, b; long long ans, res; long long c[mxn][mxn], fac[mxn]; inline void init() { int tmp = max(n, max(w, b)); for (int i = 0; i <= tmp; i++) c[i][0] = 1; for (int i = 1; i <= tmp; i++) for (int j = 1; j <= i; j++) c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % mod; fac[0] = 1; for (int i = 1; i <= max(w, b); i++) fac[i] = (i * fac[i - 1]) % mod; } int main() { scanf("%d%d%d", &n, &w, &b); init(); for (int i = 1; i <= b; i++) { long long res = n - i - 1; if (!res) break; res = res * c[b - 1][i - 1] % mod; res = res * fac[b] % mod; res = res * c[w - 1][n - i - 1] % mod; res = res * fac[w] % mod; ans = (ans + res) % mod; } printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 4005, oo = 1000000009; long long p[N], c[N][N], res, ans; int n, w, b; int main() { p[0] = 1; for (int i = 1; i < N - 2; i++) p[i] = p[i - 1] * i % oo; for (int i = 0; i < N - 2; i++) for (int j = 0; j < i + 1; j++) c[i][j] = i && j ? (c[i - 1][j - 1] + c[i - 1][j]) % oo : 1; scanf("%d%d%d", &n, &w, &b); for (int i = max(n - w, 1); i < b + 1; i++) if (i < n - 1) ans = (c[b - 1][i - 1] * c[w - 1][n - i - 1] % oo * (n - 1 - i) + ans) % oo; printf("%d\n", p[w] * p[b] % oo * ans % oo); return 0; }
#include <bits/stdc++.h> const int MOD = (int)(1e9) + 9; const int N = 4000 + 9; int f[N][N], n, c[N * 2][N], res; int fac(int x) { long long res = 1; for (int i = 1; i <= x; ++i) res = res * i % MOD; return res; } int main() { int a[2]; scanf("%d%d%d", &n, &a[1], &a[0]); for (int i = 1; i <= a[1]; ++i) f[1][i] = 1; f[0][0] = 1; for (int i = 2; i <= n; ++i) { int sum = f[i - 2][0]; for (int j = 1; j <= a[i & 1]; ++j) { f[i][j] = (f[i][j] + sum) % MOD; sum = (sum + f[i - 2][j]) % MOD; } } c[0][1] = 1; for (int i = 1; i <= a[0] + a[1]; ++i) for (int j = 1; j <= n && j <= i; ++j) c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % MOD; for (int i = 2; i < 3; ++i) res = (res + 1ll * f[i][a[i & 1]] * f[i + 1][a[i + 1 & 1]] % MOD * c[a[0] + a[1] - i][n - i] % MOD) % MOD; printf("%I64d\n", 1ll * res * fac(a[0]) % MOD * fac(a[1]) % MOD); }
#include <bits/stdc++.h> using namespace std; template <class _T> inline _T sqr(const _T &first) { return first * first; } template <class _T> inline string tostr(const _T &a) { ostringstream os(""); os << a; return os.str(); } const long double PI = 3.1415926535897932384626433832795L; const long double EPS = 1e-9; char TEMPORARY_CHAR; const int INF = 1e9; inline void fft(vector<complex<long double> > &a, bool invert) { int n = (int)a.size(); for (int i = 1, j = 0; i < n; ++i) { int bit = n >> 1; for (; j >= bit; bit >>= 1) j -= bit; j += bit; if (i < j) swap(a[i], a[j]); } for (int len = 2; len <= n; len <<= 1) { long double ang = 2 * PI / len * (invert ? -1 : 1); complex<long double> wlen(cos(ang), sin(ang)); for (int i = 0; i < n; i += len) { complex<long double> w(1); for (int j = 0; j < len / 2; ++j) { complex<long double> u = a[i + j], v = a[i + j + len / 2] * w; a[i + j] = u + v; a[i + j + len / 2] = u - v; w *= wlen; } } } if (invert) for (int i = 0; i < n; ++i) a[i] /= n; } inline void input(int &a) { a = 0; while (((TEMPORARY_CHAR = getchar()) > '9' || TEMPORARY_CHAR < '0') && (TEMPORARY_CHAR != '-')) { } char neg = 0; if (TEMPORARY_CHAR == '-') { neg = 1; TEMPORARY_CHAR = getchar(); } while (TEMPORARY_CHAR <= '9' && TEMPORARY_CHAR >= '0') { a = (a << 3) + (a << 1) + TEMPORARY_CHAR - '0'; TEMPORARY_CHAR = getchar(); } if (neg) a = -a; } inline void out(long long a) { if (!a) putchar('0'); if (a < 0) { putchar('-'); a = -a; } char s[20]; int i; for (i = 0; a; ++i) { s[i] = '0' + a % 10; a /= 10; } for (int j = (i)-1; j >= 0; j--) putchar(s[j]); } inline int nxt() { int(ret); input((ret)); ; return ret; } struct lnum { vector<int> a; int base; lnum(int num = 0, int base = 1000000000) : base(base) { if (!num) a.resize(1); while (num) { a.push_back(num % base); num /= base; } } inline int len() const { return a.size(); } lnum &operator=(const lnum &l) { if (this != &l) { a = l.a; base = l.base; } return *this; } inline friend lnum operator+(const lnum &l, const lnum &r) { lnum ret(0, l.base); int base = l.base; int ln = l.len(), rn = r.len(); int n = max(ln, rn); ret.a.resize(n); int o = 0; for (int i = 0; i < n; ++i) { int s = o; if (i < ln) s += l.a[i]; if (i < rn) s += r.a[i]; o = s >= base; if (o) s -= base; ret.a[i] = s; } if (o) ret.a.push_back(1); return ret; } inline friend lnum operator-(const lnum &l, const lnum &r) { lnum ret(0, l.base); int base = l.base; int n = l.len(); int rn = r.len(); ret.a.resize(n); int o = 0; for (int i = 0; i < n; ++i) { int s = l.a[i] - o; if (i < rn) s -= r.a[i]; o = s < 0; if (o) s += base; ret.a[i] = s; } if (ret.len() > 1 && !ret.a.back()) ret.a.pop_back(); return ret; } inline friend lnum operator*(const lnum &l, const lnum &r) { lnum ret(0, l.base); int base = l.base; if (l.len() * r.len() > 1000000) { vector<complex<long double> > fa(l.a.begin(), l.a.end()), fb(r.a.begin(), r.a.end()); int n = 1; while (n < max(l.len(), r.len())) n <<= 1; n <<= 1; fa.resize(n), fb.resize(n); fft(fa, false), fft(fb, false); for (int i = 0; i < n; ++i) fa[i] *= fb[i]; fft(fa, true); ret.a.resize(n); for (int i = 0; i < n; ++i) ret.a[i] = int(fa[i].real() + 0.5); int carry = 0; for (int i = 0; i < n; ++i) { ret.a[i] += carry; carry = ret.a[i] / base; ret.a[i] %= base; } } else { ret.a.resize(l.len() + r.len()); for (int i = 0; i < l.len(); ++i) for (int j = 0, carry = 0; j < r.len() || carry; ++j) { long long cur = ret.a[i + j] + (long long)l.a[i] * (j < r.len() ? r.a[j] : 0) + carry; ret.a[i + j] = cur % base; carry = cur / base; } } while (ret.len() > 1 && !ret.a.back()) ret.a.pop_back(); return ret; } inline friend lnum operator/(const lnum &l, const int &r) { lnum ret(0, l.base); ret.a.resize(l.len()); int carry = 0; for (int i = l.len() - 1; i >= 0; --i) { long long cur = l.a[i] + (long long)carry * l.base; ret.a[i] = cur / r; carry = cur % r; } while (ret.len() > 1 && ret.a.back() == 0) ret.a.pop_back(); return ret; } inline friend bool operator<(const lnum &l, const lnum &r) { if (l.len() < r.len()) return true; if (l.len() > r.len()) return false; int n = l.len(); for (int i = n - 1; i >= 0; --i) { if (l.a[i] < r.a[i]) return true; if (l.a[i] > r.a[i]) return false; } return false; } inline friend bool operator>(const lnum &l, const lnum &r) { return r < l; } inline friend bool operator==(const lnum &l, const lnum &r) { if (l.len() != r.len()) return false; int n = l.len(); for (int i = n - 1; i; --i) { if (l.a[i] != r.a[i]) return false; } return true; } inline friend bool operator!=(const lnum &l, const lnum &r) { return !(l == r); } inline void print() { if (base == 1000000000) { printf("%d", a.back()); for (int i = a.size() - 2; i >= 0; --i) printf("%09d", a[i]); } else { for (int i = a.size() - 1; i >= 0; --i) printf("%d", a[i]); } } }; int c[4001][4001]; int main() { int N = 4000; int mod = 1000000009; memset((c), 0, sizeof(c)); for (int i = 0; i <= N; ++i) { c[i][0] = 1; for (int j = 1; j <= i; ++j) { c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]); if (c[i][j] >= mod) c[i][j] -= mod; } } int(n); input((n)); ; int(a); input((a)); ; int(b); input((b)); ; long long ans = 0; for (int i = 1; i <= n; ++i) for (int j = 1; i + j < n; ++j) ans = (ans + (long long)c[b - 1][(n - i - j) - 1] * c[a - 1][i + j - 1]) % mod; for (int i = 0; i < (int)(a); i++) ans = ans * (i + 1) % mod; for (int i = 0; i < (int)(b); i++) ans = ans * (i + 1) % mod; cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 4003, P = 1e9 + 9; int n, w, b, jc[N << 1]; inline void in(register int &x) { int f = 0; x = 0; char c = getchar(); while (c < '0' || c > '9') f |= c == '-', c = getchar(); while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x = f ? -x : x; } inline int mi(register int x, register int k) { register int s = 1; while (k) { if (k & 1) s = (long long)s * x % P; x = (long long)x * x % P, k >>= 1; } return s; } inline int inv(register int x) { return mi(x, P - 2); } inline int C(register int m, register int n) { return (long long)jc[n] * inv(jc[n - m]) % P * inv(jc[m]) % P; } int main() { in(n), in(w), in(b), jc[0] = 1; for (register int i = 1; i <= w + b; ++i) jc[i] = (long long)jc[i - 1] * i % P; printf("%d\n", (long long)C(n - 3, w + b - 3) * (w - 1) % P * jc[w] % P * jc[b] % P); }
#include <bits/stdc++.h> using namespace std; const int modulo = 1000000009; long long A(int events, int days) { if (events < days) return 0; long long result = 1; for (int e = events - 1; e >= days; --e) { result *= e; result %= modulo; } for (int i = 0; i < days; i++) { result *= events; result %= modulo; --events; } return result; } int main() { int n, w, b; scanf("%i%i%i", &n, &w, &b); long long result = 0; for (int i = 2; i < n; i++) { result += ((i - 1) * A(w, i)) % modulo * A(b, n - i); result %= modulo; } printf("%i\n", (int)result); return 0; }
#include <bits/stdc++.h> using namespace std; long long a[4010]; long long c[4010][4010]; void geta() { int i; a[1] = 1; for (i = 2; i < 4010; i++) { a[i] = a[i - 1] * i; a[i] %= 1000000009; } } void getc() { int i, j; for (i = 0; i < 4010; i++) { for (j = 0; j <= i; j++) { if (!j || i == j) c[i][j] = 1; else c[i][j] = c[i - 1][j] + c[i - 1][j - 1]; c[i][j] %= 1000000009; } } } int main() { int n, w, b; int i, j; long long ans, nn; geta(); getc(); scanf("%d%d%d", &n, &w, &b); ans = 0; for (i = max(1, n - w); i <= min(n - 2, b); i++) { j = n - i; ans += ((c[b - 1][i - 1] * c[w - 1][j - 1]) % 1000000009) * (j - 1) % 1000000009; ans %= 1000000009; } ans = ((ans * a[b]) % 1000000009) * a[w] % 1000000009; printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long modulo(long long base, long long exponent, long long modulus); long long choose(long long n, long long k); long long inverse(long long a, long long m); void build(); void fileio(); long long ncr(long long n, long long r); const int nax = 1e6 + 10; const int LG = log2(nax) + 1; vector<long long> fact(nax); int32_t main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); build(); long long n, w, b; cin >> n >> w >> b; long long ans = 0; for (long long i = 1; i < w; i++) { long long temp = (ncr(w, i) * fact[i]) % 1000000009; temp = (temp * fact[w - i]) % 1000000009; temp = (temp * fact[b]) % 1000000009; temp = (temp * ncr(i - 1 + w - i - 1 + b - 1, n - 3)) % 1000000009; ans = (ans + temp) % 1000000009; } cout << ans << '\n'; return 0; } long long ncr(long long n, long long r) { if (r > n || r < 0 || n < 0) return 0; long long ans = fact[n]; long long temp = (fact[n - r] * fact[r]) % 1000000009; ans = (ans * inverse(temp, 1000000009)) % 1000000009; return ans; } void fileio() { freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout); } void build() { fact[0] = 1; for (long long i = 1; i < nax; i++) fact[i] = (fact[i - 1] * i) % 1000000009; } long long modulo(long long base, long long exponent, long long modulus) { if (modulus == 1) return 0; long long result = 1; base = base % modulus; while (exponent > 0) { if (exponent % 2 == 1) { result = (result * base) % modulus; } exponent = exponent >> 1; base = (base * base) % modulus; } return result; } long long choose(long long n, long long k) { if (k == 0) return 1; return (n * choose(n - 1, k - 1)) / k; } void EE(long long a, long long b, long long &co1, long long &co2) { if (a % b == 0) { co1 = 0; co2 = 1; return; } EE(b, a % b, co1, co2); long long temp = co1; co1 = co2; co2 = temp - co2 * (a / b); } long long inverse(long long a, long long m) { long long x, y; EE(a, m, x, y); if (x < 0) x += m; return x; }
#include <bits/stdc++.h> using namespace std; const int maxn = 4005; const long long mod = 1000000009; long long fact[maxn], invfact[maxn]; int w, b, n; long long power(long long x, long long y) { long long res = 1; while (y) { if (y & 1) res = res * x % mod; x = x * x % mod; y >>= 1; } return res; } long long C(int x, int y) { if (x < y) return 0; return fact[x] * invfact[y] % mod * invfact[x - y] % mod; } int main() { scanf("%d%d%d", &n, &w, &b); fact[0] = invfact[0] = 1; for (int i = 1; i < maxn; i++) { fact[i] = fact[i - 1] * i % mod; invfact[i] = power(fact[i], mod - 2); } long long ans = 0; for (int i = 1; i <= n - 2; i++) ans = (ans + C(b - 1, i - 1) * C(w - 1, n - i - 1) % mod * (n - i - 1) % mod) % mod; printf("%I64d\n", ans * fact[w] % mod * fact[b] % mod); return 0; }
#include <bits/stdc++.h> using namespace std; long long C[4444][4444]; long long n, w, b, ans; void init() { for (int i = 0; i < 4444; i++) { for (int j = 0; j <= i; j++) { if (j == 0 || j == i) { C[i][j] = 1; } else { C[i][j] = C[i - 1][j] + C[i - 1][j - 1]; if (C[i][j] > 1000000009LL) C[i][j] -= 1000000009LL; } } } } int main() { init(); cin >> n >> w >> b; for (int i = 1; i < n; i++) { for (int j = 1; j + i < n; j++) { ans = (ans + C[w - 1][n - j - 1] * C[b - 1][j - 1]) % 1000000009LL; } } for (int i = 1; i <= w; i++) { ans = ans * i % 1000000009LL; } for (int i = 1; i <= b; i++) { ans = ans * i % 1000000009LL; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1000000009; const int N = 4005; long long fac[N], ifac[N], inv[N], pw2[N]; void pre() { fac[0] = ifac[0] = fac[1] = ifac[1] = inv[1] = 1; for (int i = 2; i < N; i++) { fac[i] = i * fac[i - 1] % mod; inv[i] = inv[mod % i] * (mod - mod / i) % mod; ifac[i] = ifac[i - 1] * inv[i] % mod; } pw2[0] = 1; for (int i = 1; i < N; i++) { pw2[i] = pw2[i - 1] << 1; if (pw2[i] >= mod) pw2[i] -= mod; } } int main() { ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << setprecision(32); pre(); int n, w, b; cin >> n >> w >> b; long long ans = 0; for (int r = 1; r <= w; r++) { if (1 <= n - r && n - r <= b) { long long tmp = (fac[w - 1] * ifac[r - 1]) % mod; (tmp *= ifac[w - r]) %= mod; (tmp *= fac[b - 1]) %= mod; (tmp *= ifac[n - r - 1]) %= mod; (tmp *= ifac[b - n + r]) %= mod; (tmp *= (r - 1)) %= mod; ans += tmp; if (ans >= mod) ans -= mod; } } (ans *= fac[w]) %= mod; (ans *= fac[b]) %= mod; cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const long long maxn = 4010; const long long mod = 1e9 + 9; long long f[maxn * 2][maxn], n, w, b; long long num[maxn * 2], inv[maxn * 2]; long long pp(long long a, long long b) { if (!b) return 1; long long cnt = pp(a, b / 2); cnt = 1ll * cnt * cnt % mod; if (b & 1) cnt = 1ll * cnt * a % mod; return cnt; } long long calc(long long n, long long m) { if (n < m) return 0; return 1ll * num[n] * num[n - 1] % mod * inv[m - 1] % mod * inv[n - m] % mod; } int main() { cin >> n >> w >> b; f[1][1] = 1; for (long long i = 2; i <= w + b; ++i) for (long long j = 1; j <= min(n, i); ++j) f[i][j] = (1ll * f[i - 1][j] * j + f[i - 1][j - 1]) % mod; num[0] = 1; for (long long i = 1; i <= w + b; ++i) num[i] = 1ll * num[i - 1] * i % mod; inv[w + b] = pp(num[w + b], mod - 2); for (long long i = w + b - 1; i >= 0; --i) inv[i] = 1ll * inv[i + 1] * (i + 1) % mod; long long ans = 0; for (long long i = 1; i < n - 1; ++i) { long long cur = n - i - 1; cur = 1ll * cur * calc(w, n - i) % mod * calc(b, i) % mod; (ans += cur) %= mod; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1000000009; int Ja[4005], Jb[4005], Ja1[4005], Jb1[4005]; int main() { int n, a, b, i, ans = 0; scanf("%d%d%d", &n, &a, &b); Ja[a] = Jb[b] = Ja1[a - 1] = Jb1[b - 1] = 1; for (i = a - 1; i >= 0; i--) Ja[i] = Ja[i + 1] * (i + 1LL) % mod; for (i = b - 1; i >= 0; i--) Jb[i] = Jb[i + 1] * (i + 1LL) % mod; for (i = a - 2; i >= 0; i--) Ja1[i] = Ja1[i + 1] * (i + 1LL) % mod; for (i = b - 2; i >= 0; i--) Jb1[i] = Jb1[i + 1] * (i + 1LL) % mod; for (i = max(n - b, 2); i < n && i <= a; i++) ans = (ans + (long long)Ja1[i - 1] * Ja[a - i] % mod * Jb1[n - i - 1] % mod * Jb[b - n + i] % mod * (i - 1)) % mod; printf("%d\n", ans); }
#include <bits/stdc++.h> using namespace std; long long int w, b, x, n; long long int pp[3000000], jc[5050], jcn[5050], qq[3000000]; long long int modpow(long long int x, long long int y) { long long int p = 1, s = x; for (; y; y >>= 1) { if (y & 1) (p *= s) %= 1000000009; (s *= s) %= 1000000009; } return p; } long long int tm(long long int x, long long int y) { return (x * y) % 1000000009; } long long int tm4(long long int x, long long int y, long long int z, long long int w) { return tm(tm(x, y), tm(z, w)); } long long int C(long long int x, long long int y) { return tm(jc[x], tm(jcn[x - y], jcn[y])); } int main() { long long int i, j, k, ans = 0; cin >> n >> w >> b; for (i = jc[0] = 1; i <= 4000; i++) jc[i] = (jc[i - 1] * i) % 1000000009; for (jcn[4000] = modpow(jc[4000], 1000000009 - 2), i = 4000; i; i--) jcn[i - 1] = (jcn[i] * i) % 1000000009; for (x = 1; x <= b && x <= n - 2; x++) (ans += tm(n - x - 1, tm4(C(b - 1, x - 1), C(w - 1, n - x - 1), jc[b], jc[w]))) %= 1000000009; cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const int oo = INT_MAX >> 1; const int Mo = 1000000009; int C[4100][4100]; long long fac[4100]; int main() { int i, j; fac[0] = C[0][0] = 1; for (i = 1; i <= 4000; i++) { fac[i] = fac[i - 1] * i % Mo; C[i][0] = 1; for (j = 1; j <= i; j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= Mo) C[i][j] -= Mo; } } int N, w, b; cin >> N >> w >> b; long long ans = 0; int l = max(1, N - w), r = min(b, N); for (i = l; i <= r; i++) ans = (ans + ((long long)C[b - 1][i - 1] * fac[b] % Mo) * ((long long)C[w - 1][N - i - 1] * fac[w] % Mo * (N - i - 1) % Mo)) % Mo; cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; const long long N = 10000, M = 1000000009; long long i, j, k, l, m, n, o, p, W, B, f[N], ans, cul; inline long long ni(long long x) { long long m = M - 2, ans = 1; while (m) { if (m & 1) ans = (ans * x) % M; x = (x * x) % M; m >>= 1; } return ans; } inline long long C(long long n, long long k) { if (k > n) return 0; long long ans = f[n]; ans = (ans * ni(f[n - k])) % M; ans = (ans * ni(f[k])) % M; return ans; } int main() { cin >> n >> W >> B; ans = 0; f[0] = 1; for (i = 1; i <= 4000; i++) f[i] = (f[i - 1] * i) % M; for (i = 2; i <= n - 1; i++) { j = n - i; cul = (C(W - 1, i - 1) * f[W]) % M; cul *= (C(B - 1, j - 1) * f[B]) % M; cul %= M; cul = (cul * (i - 1)) % M; ans += cul; if (ans >= M) ans -= M; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1000000009; int n, b, w, C[4005][4005]; int main() { long long ans, x, y; cin >> n >> b >> w; C[0][0] = 1; for (int i = 1; i < 4001; i++) { C[i][0] = C[i][i] = 1; for (int j = 1; j < i; j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= mod) C[i][j] -= mod; } } ans = 0ll; for (int i = 1; i <= n - 2; i++) { x = (long long)C[b - 1][n - i - 1]; y = (long long)C[w - 1][i - 1]; ans = (ans + (((x * y) % mod) * (n - i - 1)) % mod) % mod; } for (int i = 1; i <= b; i++) ans = (ans * (long long)i) % mod; for (int i = 1; i <= w; i++) ans = (ans * (long long)i) % mod; cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 4005; const int moder = 1e9 + 9; int fact[4005]; int c[4005][4005]; int n, w, b; int ans = 0; int main() { scanf("%d%d%d", &n, &w, &b); fact[0] = 1; for (int i = 1; i < maxn; i++) fact[i] = 1LL * i * fact[i - 1] % moder; for (int i = 0; i < maxn; i++) c[i][0] = 1; for (int i = 0; i < maxn; i++) for (int j = 1; j <= i; j++) { c[i][j] = c[i - 1][j] + c[i - 1][j - 1]; if (c[i][j] >= moder) c[i][j] -= moder; } for (int i = 2; i <= n; i++) for (int j = i; j < n; j++) { int len = j - i + 1; if (n - len - 1 >= 0) ans = (ans + (1LL * fact[b] * c[b - 1][len - 1] % moder) * (1LL * fact[w] * c[w - 1][n - len - 1] % moder)) % moder; } printf("%d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long n, w, b, s, W, B, ans, c[4005][4005]; long long C(int x, int y) { if (c[x][y]) { return c[x][y]; } if (y == 0) { return c[x][y] = 1; } return c[x][y] = ((x - 1 >= y ? C(x - 1, y) : 0) + C(x - 1, y - 1)) % 1000000009; } int main() { scanf("%lld%lld%lld", &n, &w, &b); W = B = 1; for (long long i = 1; i <= w; i++) { W *= i; W %= 1000000009; } for (long long i = 1; i <= b; i++) { B *= i; B %= 1000000009; } for (long long i = max((long long)1, n - w); i <= b && i != n - 1; i++) { ans = (ans + C(b - 1, i - 1) * B % 1000000009 * C(w - 1, n - i - 1) % 1000000009 * (n - i - 1) % 1000000009 * W % 1000000009) % 1000000009; } printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const long long mo = 1000000009; int n, a, b; long long ans; long long zxy(int a, int b) { long long hzh = 1; for (int i = 1; i <= a; i++) { hzh *= b - i; hzh %= mo; } for (int i = b; i > a; i--) { hzh *= i; hzh %= mo; } return hzh; } int main() { scanf("%d%d%d", &n, &a, &b); for (int i = 1; i <= n - 2; i++) if (i <= b && n - i <= a) { long long tmp = zxy(n - i - 1, a); long long tmp2 = zxy(i - 1, b); long long sum = (tmp * tmp2) % mo; sum *= n - i - 1; sum %= mo; ans += sum; ans %= mo; } cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; inline int read() { char ch = getchar(); int x = 0, f = 1; while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); } while ('0' <= ch && ch <= '9') { x = x * 10 + ch - '0'; ch = getchar(); } return x * f; } int C[4010][4010]; int main() { int n = read(), w = read(), b = read(); for (int i = (0); i <= (4000); i++) C[i][0] = 1; for (int i = (1); i <= (4000); i++) for (int j = (1); j <= (4000); j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= 1000000009) C[i][j] -= 1000000009; } long long res = 0; for (int i = (1); i <= (n - 1); i++) { for (int j = (i + 1); j <= (n - 1); j++) { res = (res + (long long)C[w - 1][n - j + i - 1] * (long long)C[b - 1][j - i - 1]) % 1000000009; } } for (int i = (1); i <= (w); i++) res = (res * i) % 1000000009; for (int i = (1); i <= (b); i++) res = (res * i) % 1000000009; printf("%I64d\n", res); return 0; }
#include <bits/stdc++.h> using namespace std; long long int fact[1000001], ifact[1000001]; long long int bpow(long long int x, long long int n) { long long int ans = 1; while (n > 0) { if (n & 1) ans *= x; x *= x; ans %= 1000000009; x %= 1000000009; n /= 2; } return ans; } void pre_calc(long long int N) { fact[0] = ifact[0] = 1; for (long long int i = 1; i <= N; ++i) { fact[i] = (fact[i - 1] * i) % 1000000009; ifact[i] = bpow(fact[i], 1000000009 - 2); } } long long int ncr(int n, int r) { if (r < 0 or n < r) return 0; long long int ans = fact[n]; ans = (ans * ifact[r]) % 1000000009; ans = (ans * ifact[n - r]) % 1000000009; return ans; } int main() { long long int n, w, b, i, j, blen, wlen, temp, ans = 0; pre_calc(100000); cin >> n >> w >> b; for (i = 1; i <= n - 2; i++) { for (j = i + 1; j < n; j++) { blen = j - i; wlen = n - blen; temp = ncr(b - 1, b - blen); temp *= ncr(w - 1, w - wlen); temp %= 1000000009; ans += temp; ans %= 1000000009; } } ans *= fact[w]; ans %= 1000000009; ans *= fact[b]; ans %= 1000000009; cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1e9 + 9; long long c[4005][4005]; void getc() { memset(c, 0, sizeof(c)); c[0][0] = 1; for (int i = 1; i < 4001; i++) { c[i][0] = 1; for (int j = 1; j <= i; j++) { c[i][j] = (c[i - 1][j - 1] + c[i - 1][j]) % mod; } } } long long a[4005]; void geta() { a[0] = 1; a[1] = 1; for (long long i = 2; i <= 4000; i++) a[i] = a[i - 1] * i % mod; } int main() { getc(); geta(); int n, w, b; while (scanf("%d%d%d", &n, &w, &b) == 3) { int x = max(1, n - w), y = min(b, n - 2); long long ans = 0; for (int i = x; i <= y; i++) { ans = (ans + c[b - 1][i - 1] * c[w - 1][n - i - 1] % mod * (n - i - 1) % mod) % mod; } ans = ans * a[w] % mod * a[b] % mod; printf("%lld\n", ans); } return 0; }
#include <bits/stdc++.h> using namespace std; const int MAX_N = 4000; const int MAX_N2 = MAX_N * 2; const int MOD = 1000000009; int fs[MAX_N2 + 1], invfs[MAX_N2 + 1]; int powmod(int a, int n) { int pm = 1; while (n > 0) { if (n & 1) pm = (long long)pm * a % MOD; a = (long long)a * a % MOD; n >>= 1; } return pm; } inline int npk(int n, int k) { return (long long)fs[n] * invfs[n - k] % MOD; } inline int nck(int n, int k) { return (long long)fs[n] * invfs[n - k] % MOD * invfs[k] % MOD; } inline int nhk(int n, int k) { return nck(n + k - 1, k); } int main() { fs[0] = invfs[0] = 1; for (int i = 1; i <= MAX_N2; i++) { fs[i] = (long long)fs[i - 1] * i % MOD; invfs[i] = powmod(fs[i], MOD - 2); } int n, w, b; scanf("%d%d%d", &n, &w, &b); int sum = 0; for (int i = max(2, n - b), j = n - i; i <= w && j >= 1; i++, j--) { int d = (long long)nhk(i, w - i) * nhk(j, b - j) % MOD * (i - 1) % MOD; sum = (sum + d) % MOD; } int ans = (long long)sum * fs[w] % MOD * fs[b] % MOD; printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1000000009; int n, w, b; long long c[4005][4005]; long long ans = 0; int main() { int i, j, k; scanf("%d%d%d", &n, &w, &b); for (i = 0; i < (4001); i++) { for (j = 0; j < (i + 1); j++) { if (j == 0 || j == i) { c[i][j] = 1; continue; } c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % mod; } } for (i = 1; i < n; i++) { for (j = 1; i + j < n; j++) { k = n - i - j; ans = (ans + c[w - 1][i + k - 1] * c[b - 1][j - 1]) % mod; } } for (i = 1; i <= (w); i++) ans = ans * i % mod; for (i = 1; i <= (b); i++) ans = ans * i % mod; printf("%I64d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; int choose(int k, int n) { static int F[4003][4003], FF[4003][4003]; if (k == 0 || k == n) return 1; if (k < 0 || k > n) return 0; if (FF[k][n]++) return F[k][n]; F[k][n] = (choose(k - 1, n - 1) + choose(k, n - 1)) % 1000000009; return F[k][n]; } int fact(int n) { static int F[4003], FF[4003]; if (n == 0) return 1; if (FF[n]++) return F[n]; F[n] = 1LL * fact(n - 1) * n % 1000000009; return F[n]; } long long f(int m, int n) { long long r = 1LL * fact(m) * choose(n - 1, m - 1) % 1000000009; return r; } int n, A, B; long long Answer = 0; int main() { scanf("%d%d%d", &n, &A, &B); for (int i = 1; i <= n - 2; i++) { Answer += 1LL * f(B, i) * f(A, n - i) % 1000000009 * (n - i - 1) % 1000000009; Answer %= 1000000009; } cout << Answer << endl; }
#include <bits/stdc++.h> using namespace std; const long long MOD = 1e9 + 9; long long C[4010][4010]; long long n, x, y; long long func(int a, int b) { return C[a - 1][b - 1]; } int main() { cin >> n >> x >> y; for (int i = 0; i <= 4005; i++) { for (int j = 0; j <= i; j++) { if (i == j) { C[i][j] = 1; } else if (j == 0) { C[i][j] = 1; } else { C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % MOD; } } } long long ans = 0ll; for (int i = 1; i < n; i++) { for (int j = 1; i + j < n; j++) { int k = n - i - j; ans = (ans + func(x, i + k) * func(y, j)) % MOD; } } for (int i = 1; i <= x; i++) { ans = ans * i % MOD; } for (int i = 1; i <= y; i++) { ans = ans * i % MOD; } cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1e9 + 9; int n, m, z, x, y, mai, maj; long long f[4005][4005], c[4005][4005], jc[4005], ans; int main() { scanf("%d%d%d", &n, &x, &y); c[0][0] = 1; for (int i = 1; i <= 4000; ++i) for (int j = 0; j <= i; ++j) { if (j != 0) c[i][j] = (c[i - 1][j - 1] + c[i - 1][j]) % mod; else c[i][j] = c[i - 1][j]; } jc[0] = 1; for (int i = 1; i <= 4000; ++i) jc[i] = (jc[i - 1] * i) % mod; mai = min(x - 1, n - 2); ans = 0; for (int i = 1; i <= mai; ++i) { maj = min(x - 1, n - i - 1); for (int j = 1; j <= maj; ++j) ans = (ans + c[y - 1][n - i - j - 1] * c[x - 1][i + j - 1]) % mod; } ans = ans * jc[x] % mod * jc[y] % mod; printf("%I64d", ans); }
#include <bits/stdc++.h> using namespace std; const int md = 1000000009; long long c[4010][4010]; long long f(int i, int j) { return c[i - 1][j - 1]; } int main() { int n, w, b, k; for (int i = 0; i < 4010; i++) { for (int j = 0; j <= i; j++) { if (j == 0 || j == i) { c[i][j] = 1; } else { c[i][j] = (c[i - 1][j - 1] + c[i - 1][j]) % md; } } } cin >> n >> w >> b; long long ans = 0; for (int i = 1; i < n; i++) { for (int j = 1; j < n - i; j++) { k = n - i - j; ans = (ans + f(w, i + k) * f(b, j)) % md; } } for (int i = 1; i <= w; i++) { ans = ans * i % md; } for (int i = 1; i <= b; i++) { ans = ans * i % md; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = ~0U >> 1; const long long INF = ~0ULL >> 1; ; const double pi = acos(-1.0); template <class T> inline T sqr(T a) { return a * a; } template <class T> inline void read(T &n) { char c; for (c = getchar(); !(c >= '0' && c <= '9'); c = getchar()) ; n = c - '0'; for (c = getchar(); c >= '0' && c <= '9'; c = getchar()) n = n * 10 + c - '0'; } int Pow(int base, int n, int mo) { if (n == 0) return 1; if (n == 1) return base; int tmp = Pow(base, n >> 1, mo); tmp = (long long)tmp * tmp % mo; if (n & 1) tmp = (long long)tmp * base % mo; return tmp; } struct point { int x, y; point() {} point(int _x, int _y) : x(_x), y(_y) {} }; const int mo = 1000000009, maxn = 5000; long long ans; int n, a, b, inv[maxn], fac[maxn], f[maxn], g[maxn]; int C(int n, int m) { if (n < m) return 0; if (n == 0) return 1; long long ret = fac[n]; ret = ret * inv[m] % mo; ret = ret * inv[n - m] % mo; return int(ret); } int main() { scanf("%d%d%d", &n, &a, &b); fac[0] = 1; for (int i = (1); i <= (4000); ++i) fac[i] = (long long)fac[i - 1] * i % mo; for (int i = (0); i <= (4000); ++i) inv[i] = Pow(fac[i], mo - 2, mo); for (int i = (1); i <= (n); ++i) f[i] = C(a - 1, i - 1); for (int i = (1); i <= (n); ++i) g[i] = C(b - 1, i - 1); for (int i = (1); i <= (n); ++i) for (int j = (i + 1); j <= (n - 1); ++j) { ans += (long long)f[i + n - j] * g[j - i] % mo; ans %= mo; } ans = ans * fac[a] % mo * fac[b] % mo; printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int p = 1000000009, maxn = 4010; int cw[maxn], cb[maxn], inv[maxn], prm[maxn], tot, n, m, w, b; int pow(int x, int k) { int ret = 1; for (; k; k >>= 1, x = (long long)x * x % p) if (k & 1) ret = (long long)ret * x % p; return ret; } int main() { int ans = 0; scanf("%d%d%d", &n, &w, &b); m = max(w, b); inv[1] = 1; for (int i = 2; i <= m; i++) { if (!inv[i]) { inv[i] = pow(i, p - 2); prm[++tot] = i; } for (int j = 1; i * prm[j] <= m; j++) { inv[i * prm[j]] = (long long)inv[i] * inv[prm[j]] % p; if (i % prm[j] == 0) break; } } cw[0] = 1; for (int i = 1; i < w; i++) cw[i] = (long long)cw[i - 1] * inv[i] % p * (w - i) % p; cb[0] = 1; for (int i = 1; i < b; i++) cb[i] = (long long)cb[i - 1] * inv[i] % p * (b - i) % p; for (int i = max(1, n - w); i <= n - 2 && i <= b; i++) ans = (ans + (long long)(n - i - 1) * cw[n - i - 1] % p * cb[i - 1]) % p; for (int i = 2; i <= b; i++) ans = (long long)ans * i % p; for (int i = 2; i <= w; i++) ans = (long long)ans * i % p; printf("%d\n", ans); }
#include <bits/stdc++.h> using namespace std; int n, m, w, b; int C[8020][8020], f[8020 << 1]; void init() { C[0][0] = 1; for (int i = 1; i < 8020; i++) { C[i][0] = C[i][i] = 1; for (int j = 1; j < i; j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= 1000000009) C[i][j] -= 1000000009; } } f[0] = 1; for (int i = 1; i < 8020; i++) f[i] = 1LL * f[i - 1] * i % 1000000009; } int main() { init(); cin >> n >> w >> b; long long ans = 0; for (int i = 1; i < w; i++) { ans += 1LL * C[w + b - 3][n - 3] * C[w][i] % 1000000009 * f[i] % 1000000009 * f[b] % 1000000009 * f[w - i] % 1000000009; if (ans >= 1000000009) ans -= 1000000009; } cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; inline int get() { int f = 0, v = 0; char ch; while (!isdigit(ch = getchar())) if (ch == '-') break; if (ch == '-') f = 1; else v = ch - '0'; while (isdigit(ch = getchar())) v = v * 10 + ch - '0'; if (f == 1) return -v; else return v; } const int maxn = 4003, mod = 1000000009; int n, w, b, m; long long fac[maxn], inv[maxn], ans = 0; long long C(int k, int n) { if (n < k) return 0; return fac[n] * inv[n - k] % mod * inv[k] % mod; } long long Pow(long long a, long long b) { long long res = 1; for (; b; b /= 2, a = a * a % mod) if (b & 1) res = res * a % mod; return res; } int main() { scanf("%d%d%d", &n, &w, &b); m = max(w, b); fac[0] = 1; for (int i = 1; i <= m; i++) fac[i] = fac[i - 1] * i % mod; inv[m] = Pow(fac[m], mod - 2); for (int i = m - 1; i >= 0; i--) inv[i] = inv[i + 1] * (i + 1) % mod; for (int i = 1; i <= n - 2; i++) ans = (C(n - i - 1, w - 1) * (n - i - 1) % mod * C(i - 1, b - 1) + ans) % mod; cout << ans * fac[b] % mod * fac[w] % mod << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 4010, mod = 1e9 + 9; long long ksm(long long sum, int num) { long long ans = 1; while (num) { if (num & 1) ans = ans * sum % mod; sum = sum * sum % mod; num >>= 1; } return ans; } int i, j, k, n, m, a, b; long long jc[maxn], ny[maxn]; long long ans = 0; void init() { jc[0] = 1; for (int i = 1; i < maxn; i++) jc[i] = jc[i - 1] * i % mod; ny[maxn - 1] = ksm(jc[maxn - 1], mod - 2); for (int i = maxn - 2; i >= 0; i--) ny[i] = ny[i + 1] * (i + 1) % mod; } long long C(int A, int B) { if (B > A) return 0; return jc[A] * ny[B] % mod * ny[A - B] % mod; } long long make(int A, int B) { return C(A - 1, B - 1) % mod; } int main() { cin >> n >> a >> b; init(); for (i = 2; i < n; i++) for (j = i; j < n; j++) { int lenb = (j - i) + 1, lena = n - lenb; ans += make(b, lenb) * make(a, lena) % mod; ans %= mod; } cout << ans * (jc[a] * jc[b] % mod) % mod << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int n, w, b; int fac[4044], c[4044][4044]; struct modular_arithmetic { int mod; modular_arithmetic() { mod = 1000000009; } int add(int x, int y) { return (x += y) < mod ? x : x - mod; } int mul(int x, int y) { return (int)((long long int)x * y % mod); } }; modular_arithmetic ma; int f(int n, int m) { return ma.mul(fac[m], c[m - 1][n - 1]); } int main() { scanf("%d%d%d", &n, &w, &b); int lim = max(w, b); fac[0] = fac[1] = 1; for (int i = 2; i <= lim; i++) fac[i] = ma.mul(fac[i - 1], i); for (int i = 0; i <= lim; i++) { c[i][0] = c[i][i] = 1; for (int j = 1; j < i; j++) c[i][j] = ma.add(c[i - 1][j], c[i - 1][j - 1]); } int ans = 0; for (int lb = max(1, n - w); lb <= min(n - 2, b); lb++) { int cb = 0; cb = ma.add(cb, f(lb, b)); int cw = 0; cw = ma.add(cw, f(n - lb, w)); cw = ma.mul(cw, n - lb - 1); ans = ma.add(ans, ma.mul(cb, cw)); } printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int oo = INT_MAX >> 1; const int Mo = 1000000009; long long C[4100][4100]; long long fac[4100]; int main() { int i, j; fac[0] = C[0][0] = 1; for (i = 1; i <= 4000; i++) { fac[i] = fac[i - 1] * i % Mo; C[i][0] = 1; for (j = 1; j <= i; j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= Mo) C[i][j] -= Mo; } } int N, w, b; cin >> N >> w >> b; long long ans = 0; int l = max(1, N - w), r = min(b, N); for (i = l; i <= r; i++) ans = (ans + ((long long)C[b - 1][i - 1] * fac[b] % Mo) * ((long long)C[w - 1][N - i - 1] * fac[w] % Mo * (N - i - 1) % Mo)) % Mo; cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; int INP, AM, REACHEOF; char BUF[(1 << 12) + 1], *inp = BUF; const long double PI = acos((long double)-1.0); const long long MOD = 1000000009LL; int n, w, b; long long gt[4011], revgt[4011]; long long power(long long x, long long k) { if (k == 0) return 1; if (k == 1) return x % MOD; long long mid = power(x, k >> 1); mid = (mid * mid) % MOD; if (k & 1) return (mid * x) % MOD; else return mid; } long long get(int n, int k) { return gt[n] * gt[n - 1] % MOD * revgt[k - 1] % MOD * revgt[n - k] % MOD; } int main() { gt[0] = 1; for (int i = (1), _b = (4000); i <= _b; i++) gt[i] = (gt[i - 1] * i) % MOD; for (int i = (0), _b = (4000); i <= _b; i++) revgt[i] = power(gt[i], MOD - 2); while (cin >> n >> w >> b) { long long res = 0; for (int y = (1), _b = (n - 2); y <= _b; y++) if (b >= y && n - y <= w) { int xz = n - y; long long now = (n - y) - 2 + 1; now = (now * get(w, xz)) % MOD * get(b, y) % MOD; res = (res + now) % MOD; } cout << res << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; int T[50], J, m, n, i, j, k, l, r, K, K0, x, y, first, second, xx, yy; int D[4001][4001]; long long A = 0; int main() { cin >> n >> x >> y; m = (x > y ? x : y); D[0][0] = 1; for (i = 1; i <= m; i++) for (j = i; j <= m; j++) D[i][j] = (D[i][j - 1] + D[i - 1][j - 1]) % 1000000009ll; for (i = 2; i < n; i++) for (j = i; j < n; j++) A = (A + (long long)D[j - i + 1][y] * D[n - j + i - 1][x]) % 1000000009ll; for (i = 1; i <= x; i++) A = (A * i) % 1000000009ll; for (i = 1; i <= y; i++) A = (A * i) % 1000000009ll; cout << A << endl; return 0; }
#include <bits/stdc++.h> using namespace std; long long wdp[4001][4001], bdp[4001][4001]; long long mod = 1e9 + 9; int main() { int n, b, w; cin >> n >> w >> b; wdp[0][0] = 1; bdp[0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = i; j <= w; j++) { wdp[i][j] = (wdp[i - 1][j - 1] + wdp[i][j - 1]) * (w - j + 1); wdp[i][j] %= mod; } } for (int i = 1; i <= n; i++) { for (int j = i; j <= b; j++) { bdp[i][j] = (bdp[i - 1][j - 1] + bdp[i][j - 1]) * (b - j + 1); bdp[i][j] %= mod; } } long long ans = 0; for (int i = 1; i < n; i++) { ans = (ans + (wdp[i][w] * bdp[n - i][b] % mod) * (i - 1)) % mod; ; } cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; const int N = 4003, P = 1e9 + 9; int n, w, b, jc[N << 1]; inline void in(register int &x) { int f = 0; x = 0; char c = getchar(); while (c < '0' || c > '9') f |= c == '-', c = getchar(); while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x = f ? -x : x; } inline int mi(register int x, register int k) { register int s = 1; while (k) { if (k & 1) s = (long long)s * x % P; x = (long long)x * x % P, k >>= 1; } return s; } inline int inv(register int x) { return mi(x, P - 2); } inline int C(register int m, register int n) { return (long long)jc[n] * inv(jc[n - m]) % P * inv(jc[m]) % P; } int main() { in(n), in(w), in(b), jc[0] = 1; for (register int i = 1; i <= w + b; ++i) jc[i] = (long long)jc[i - 1] * i % P; printf("%d\n", (long long)C(n - 3, w + b - 3) * (w - 1) % P * jc[w] % P * jc[b] % P); }
#include <bits/stdc++.h> using namespace std; const int maxn = 4e3 + 5, mod = 1e9 + 9; long long fac[maxn], ine[maxn]; int n, w, b; long long ans; long long pow(long long x, int k) { long long ret = 1; for (int i = k; i; i >>= 1, x = x * x % mod) if (i & 1) ret = ret * x % mod; return ret; } void prepare() { int m = max(n, max(w, b)); fac[0] = 1; for (int i = 1; i <= m; i++) fac[i] = fac[i - 1] * i % mod; ine[m] = pow(fac[m], mod - 2); for (int i = m - 1; i >= 0; i--) ine[i] = ine[i + 1] * (i + 1) % mod; } long long C(int x, int y) { return fac[x] * ine[x - y] % mod * ine[y] % mod; } int main() { scanf("%d%d%d", &n, &w, &b); prepare(); for (int i = 1; i <= n - 2; i++) { int j = n - i; if (i > b || j > w) continue; ans = (ans + C(b - 1, i - 1) * C(w - 1, j - 1) % mod * (j - 1) % mod) % mod; } ans = ans * fac[w] % mod * fac[b] % mod; printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long JC[4001], ans; int n, C[4001][4001], m, p; inline int Add(int x) { return x < 1000000009 ? x : x - 1000000009; } int main() { cin >> n >> m >> p; for (int i = 0; i < 4001; i++) C[i][0] = 1; for (int i = 1; i < 4001; i++) for (int j = 1; j <= i; j++) C[i][j] = Add(C[i - 1][j - 1] + C[i - 1][j]); JC[0] = 1; for (int i = 1; i < 4001; i++) JC[i] = JC[i - 1] * i % 1000000009; for (int i = 2; i < n; i++) ans = (ans + C[m - 1][i - 1] * JC[m] % 1000000009 * C[p - 1][n - i - 1] % 1000000009 * JC[p] % 1000000009 * (i - 1) % 1000000009) % 1000000009; cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; int qp(int a, int b) { int ans = 1; do { if (b & 1) ans = 1ll * ans * a % 1000000009; a = 1ll * a * a % 1000000009; } while (b >>= 1); return ans; } int main() { int n, w, b; scanf("%d%d%d", &n, &w, &b); int ans = w - 1; for (int i = 1; i <= w; i++) ans = 1ll * ans * i % 1000000009; for (int i = 1; i <= b; i++) ans = 1ll * ans * i % 1000000009; for (int i = w + b - 3; i >= w + b - n + 1; i--) ans = 1ll * ans * i % 1000000009; for (int i = 1; i <= n - 3; i++) ans = 1ll * ans * qp(i, 1000000009 - 2) % 1000000009; printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> const int N = 4005; const int Mod = 1000000009; int n, w, b; long long jc(int x) { long long res = 1; int i; for (i = 1; i <= x; i++) { res *= i; res %= Mod; } return res; } long long inv(long long x) { int ci = Mod - 2; long long res = 1; while (ci) { if (ci & 1) { res *= x; res %= Mod; } x *= x; x %= Mod; ci >>= 1; } return res; } long long zuhe(int x, int y) { long long res = jc(x); res *= inv(jc(y)); res %= Mod; res *= inv(jc(x - y)); res %= Mod; return res; } int main() { int i, j; scanf("%d%d%d", &n, &w, &b); long long ans = w - 1; ans *= jc(w); ans %= Mod; ans *= jc(b); ans %= Mod; ans *= zuhe(w + b - 3, n - 3); ans %= Mod; int ansx = ans; printf("%d\n", ansx); return 0; }
#include <bits/stdc++.h> using namespace std; const int MaxN = 4010; const int MOD = 1000000009; int n, w, b; long long p[MaxN], r[MaxN]; long long power(long long x, long long y) { if (!y) return 1; long long t = power(x, y / 2); t = t * t % MOD; if (y & 1) t = t * x % MOD; return t; } long long C(long long n, long long m) { return p[n] * r[m] % MOD * r[n - m] % MOD; } int main() { cin >> n >> w >> b; for (int i = p[0] = r[0] = 1; i < MaxN; ++i) { p[i] = p[i - 1] * i % MOD; r[i] = power(p[i], MOD - 2); } long long ans = 0; for (int i = max(1, n - w); i <= min(n - 2, b); ++i) ans += p[w] * p[b] % MOD * (n - i - 1) % MOD * C(b - 1, i - 1) % MOD * C(w - 1, n - i - 1) % MOD; cout << ans % MOD << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int C[4100][4100]; int F[4100]; int main() { int n, w, b; scanf("%d%d%d", &n, &w, &b); int ans = 0; for (int i = 0; i < 4100; i++) { C[i][0] = 1; for (int j = 1; j <= i; j++) { C[i][j] = C[i - 1][j] + C[i - 1][j - 1]; if (C[i][j] >= 1000000009) C[i][j] -= 1000000009; } } F[0] = 1; for (int i = 1; i < 4100; i++) { F[i] = (long long)F[i - 1] * i % 1000000009; } for (int j = 1; j <= min(b, n - 2); j++) { if (w >= n - j) { long long cur = ((long long)C[w - 1][w - (n - j)] * C[b - 1][b - j]) % 1000000009; cur = cur * (n - j - 1) % 1000000009; cur = cur * F[w] % 1000000009; cur = cur * F[b] % 1000000009; ans += (int)cur; if (ans >= 1000000009) ans -= 1000000009; } } printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 200004; long long inv[N], fac[N], fnv[N], mod = 1000000009; long long C(int n, int m) { if (n < m) return 0; return fac[n] * fnv[m] % mod * fnv[n - m] % mod; } int n, m, k; int main() { for (int i = 0; i < 2; i++) fac[i] = inv[i] = fnv[i] = 1; for (int i = 2; i < N; i++) { fac[i] = fac[i - 1] * i % mod; inv[i] = (mod - mod / i) * inv[mod % i] % mod; fnv[i] = fnv[i - 1] * inv[i] % mod; } scanf("%d %d %d", &n, &m, &k); long long ans = 0; for (int i = 1; i <= m - 1; i++) { long long t = C(m + k - 3, n - 3) * C(m, i) % mod * fac[i] % mod * fac[m - i] % mod * fac[k] % mod; ans = (ans + t) % mod; } printf("%lld\n", ans); }
#include <bits/stdc++.h> using namespace std; long long c[4002][4002], b, w, n, ans; int main() { for (int i = 1; i <= 4000; i++) { c[i][1] = c[i][i] = 1; for (int j = 2; j < i; j++) { c[i][j] = c[i - 1][j - 1] + c[i - 1][j]; if (c[i][j] >= 1000000009) c[i][j] -= 1000000009; } } scanf("%I64d%I64d%I64d", &n, &w, &b); for (int i = 1; i < n; i++) { for (int j = 1; j < n - i; j++) { ans += c[w][n - j] * c[b][j]; ans %= 1000000009; } } for (long long i = 2; i <= w; i++) ans *= i, ans %= 1000000009; for (long long i = 2; i <= b; i++) ans *= i, ans %= 1000000009; printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; inline long long max(long long a, long long b) { return a > b ? a : b; } inline long long min(long long a, long long b) { return a > b ? b : a; } template <typename T> inline int read(T& res) { long long x = 0, f = 1, flag = 0; char ch; flag = ch = getchar(); if (flag == -1) return -1; while (ch < '0' || ch > '9') { if (ch == '-') f = -1; flag = ch = getchar(); if (flag == -1) return -1; } while (ch >= '0' && ch <= '9' && flag != -1) { x = (x << 1) + (x << 3) + (ch ^ 48); flag = ch = getchar(); } res = x * f; return flag; } template <typename T, typename... Args> inline int read(T& t, Args&... a) { int res; res = read(t); if (res == -1) return -1; res = read(a...); return res; } const int maxn = 5511, mod = 1e9 + 9; long long n, m, k; long long qpow(long long x, long long y) { long long ans = 1; while (y) { if (y & 1) ans = (ans * x) % mod; y >>= 1; x = (x * x) % mod; } return ans % mod; } long long A1, A2, C1[maxn], C2[maxn], w, b; inline void solve() { long long ans = 0, mx = max(w, b); A1 = A2 = 1; for (int i = 2; i <= w; i++) A1 = (A1 * i) % mod; for (int i = 2; i <= b; i++) A2 = (A2 * i) % mod; C1[2] = w - 1; C2[2] = b - 1; C1[1] = C2[1] = 1; for (int i = 3; i <= mx; i++) { long long inv = qpow(i - 1, mod - 2); C1[i] = (C1[i - 1] * (w - i + 1) % mod * inv) % mod, C2[i] = (C2[i - 1] * (b - i + 1) % mod * inv) % mod; } int lim = max(1, n - w); for (int x = min(n - 2, b); x >= lim; x--) { ans = (ans + (((((n - x - 1) * A1 % mod) * C1[n - x] % mod) * A2) % mod) * C2[x]) % mod; } cout << ans << endl; } int main() { ios::sync_with_stdio(0), cin.tie(0), cout.tie(0); int t = 1; while (cin >> n >> w >> b) solve(); }
#include <bits/stdc++.h> const long long MOD = 1e9 + 9; const int NMAX = 4020; int fac[NMAX], inv[NMAX]; int n, w, b, ans; void calfac() { fac[0] = 1; for (int i = 1; i < NMAX; i++) fac[i] = (long long)i * fac[i - 1] % MOD; } void calinv() { inv[0] = inv[1] = 1; for (int i = 2; i < NMAX; i++) { inv[i] = MOD - (long long)(MOD / i) * inv[MOD % i] % MOD; } for (int i = 1; i < NMAX; i++) inv[i] = (long long)inv[i - 1] * inv[i] % MOD; } int cnm(int n, int m) { return (long long)fac[n] * inv[m] % MOD * inv[n - m] % MOD; } int main() { calfac(); calinv(); scanf("%d%d%d", &n, &w, &b); for (int i = 1; i <= b; i++) { if (n - i >= 2 && n - i <= w) ans = ((long long)ans + (long long)(n - i - 1) * cnm(b - 1, i - 1) % MOD * cnm(w - 1, n - i - 1) % MOD) % MOD; } ans = (long long)ans * fac[w] % MOD * fac[b] % MOD; printf("%d", ans); }
#include <bits/stdc++.h> using namespace std; const long long mod = 1000000009; long long fac[8080]; long long ex(int a, int n) { if (n == 0) return 1; long long res = ex(a, n / 2); res *= res; res %= mod; if (n % 2 == 1) res *= a; res %= mod; return res; } long long inv(int a) { return ex(a, mod - 2); } long long C(int n, int k) { long long res = fac[n]; res *= inv(fac[k]); res %= mod; res *= inv(fac[n - k]); return res % mod; } int main() { fac[0] = 1; for (int i = 1; i < 8080; i++) { fac[i] = fac[i - 1] * i; fac[i] %= mod; } int N, W, B; scanf("%d%d%d", &N, &W, &B); long long ans = 0; long long coe = (fac[W] * fac[B]) % mod; for (int x = 1; x <= N - 2; x++) { if (x > B || N - x > W) continue; long long tmp = C(B - 1, x - 1) * C(W - 1, N - x - 1); tmp %= mod; tmp *= (N - x - 1); tmp %= mod; ans += coe * tmp; ans %= mod; } ans += mod; ans %= mod; printf("%d\n", (int)ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int modi = 1000000009; const int N = 4010; int n, w, b, c, WC[N], BC[N], ni[N], ans, i; int main() { scanf("%d%d%d", &n, &w, &b); for (ni[1] = 1, i = 2; i < N; i++) ni[i] = (-(modi / i) * (long long)ni[modi % i] % modi + modi) % modi; c = 1; for (i = 1; i <= w; i++) c = (long long)c * i % modi; for (i = 1; i <= b; i++) c = (long long)c * i % modi; for (WC[0] = 1, i = 1; i <= w - 1; i++) WC[i] = (long long)WC[i - 1] * (w - i) % modi * ni[i] % modi; for (BC[0] = 1, i = 1; i <= b - 1; i++) BC[i] = (long long)BC[i - 1] * (b - i) % modi * ni[i] % modi; for (i = 1; i <= min(b, n - 1); i++) { ans = (ans + (long long)BC[i - 1] * WC[n - i - 1] % modi * c % modi * (n - i - 1)) % modi; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int n, w, b; long long f[4010], ans, c[4010][4010]; int main() { scanf("%d%d%d", &n, &w, &b), f[0] = 1; for (int i = 0; c[i][0] = 1, i <= 4000; i++) for (int j = 1; j <= i; j++) c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % 1000000009; for (int i = 1; i <= n; i++) (ans += c[w - 1][n - 1 - i] * c[b - 1][i - 1] % 1000000009 * (n - 1 - i) % 1000000009) %= 1000000009; for (int i = 1; i <= w; i++) (ans *= i) %= 1000000009; for (int i = 1; i <= b; i++) (ans *= i) %= 1000000009; printf("%lld\n", ans); fclose(stdin), fclose(stdout); return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1000000009, N = 4005; int cal[N][N], fac[N]; inline int add(int a, int b) { if (a < 0) a += mod; if (b < 0) b += mod; int ret = a + b; if (ret >= mod) return ret %= mod; else return ret; } inline int mul(int a, int b) { if (a < 0) a += mod; if (b < 0) b += mod; long long ret = (long long)a * b; if (ret >= mod) return ret % mod; else return ret; } int main() { memset(cal, 0, sizeof(cal)); cal[0][0] = 1; fac[0] = 1; for (int i = 1; i < N; i++) { fac[i] = mul(fac[i - 1], i); cal[i][0] = cal[i][i] = 1; for (int j = 1; j < i; j++) { cal[i][j] = add(cal[i - 1][j], cal[i - 1][j - 1]); } } int n, a, b, ans = 0; scanf("%d%d%d", &n, &a, &b); for (int i = 1; i < n - 1; i++) { for (int j = i + 2; j <= n; j++) { int cntb = j - i - 1, cnta = n - cntb; if (cntb > b) break; if (cnta > a) continue; ans = add(ans, mul(mul(cal[a - 1][cnta - 1], fac[a]), mul(cal[b - 1][cntb - 1], fac[b]))); } } printf("%d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long n, w, b, C[4011][4011], ans; int main() { C[0][1] = 1; for (int i = 1; i <= 4000; i++) for (int j = 1; j <= i; j++) C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % 1000000009; cin >> n >> w >> b; for (int i = 1; i <= min(n - 2, b); i++) ans = (ans + C[b][i] * C[w][n - i] % 1000000009 * (n - i - 1) % 1000000009) % 1000000009; for (int i = 1; i <= w; i++) ans = ans * i % 1000000009; for (int i = 1; i <= b; i++) ans = ans * i % 1000000009; cout << ans; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1e9 + 9; template <class T> inline bool read(T &ret) { char c; int sgn; if (c = getchar(), c == EOF) return 0; while (c != '-' && (c < '0' || c > '9')) c = getchar(); sgn = (c == '-') ? -1 : 1; ret = (c == '-') ? 0 : (c - '0'); while (c = getchar(), c >= '0' && c <= '9') ret = ret * 10 + (c - '0'); ret *= sgn; return 1; } const int maxn = 4100; long long c[maxn][maxn], fac[maxn]; void init(long long m) { for (int i = 0; i <= m; i++) { c[i][0] = 1; } for (int i = 1; i <= m; i++) { for (int j = 1; j <= i; j++) { c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % mod; } } fac[0] = 1; for (long long i = 1; i <= m; i++) { fac[i] = (fac[i - 1] * i) % mod; } } int main() { long long n, w, b; read(n), read(w), read(b); init(max(n, max(w, b)) + 1); long long ans = 0; for (long long i = 1; i <= b; i++) { long long tmp = n - i - 1; if (!tmp) break; tmp = (tmp * c[b - 1][i - 1]) % mod; tmp = (tmp * fac[b]) % mod; tmp = (tmp * c[w - 1][n - i - 1]) % mod; tmp = (tmp * fac[w]) % mod; ans = (ans + tmp) % mod; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; template <int MOD = 1000000009> struct ModInteger { int x; ModInteger(int x = 0) : x(x) {} int getValue() { return x; } void operator=(const int v) { x = v; } ModInteger operator+(const int v) { return ModInteger(x >= MOD - v ? x - MOD + v : x + v); } ModInteger operator+(const ModInteger &rhs) { return ModInteger(x >= MOD - rhs.x ? x - MOD + rhs.x : x + rhs.x); } void operator+=(const int v) { x = x >= MOD - v ? x - MOD + v : x + v; } void operator+=(const ModInteger &rhs) { x = x >= MOD - rhs.x ? x - MOD + rhs.x : x + rhs.x; } ModInteger operator-(const int v) { return ModInteger(x < v ? x - v + MOD : x - v); } ModInteger operator-(const ModInteger &rhs) { return ModInteger(x < rhs.x ? x - rhs.x + MOD : x - rhs.x); } void operator-=(const int v) { x = x < v ? x - v + MOD : x - v; } void operator-=(const ModInteger &rhs) { x = x < rhs.x ? x - rhs.x + MOD : x - rhs.x; } ModInteger operator*(const int v) { return ModInteger((long long)x * v % MOD); } ModInteger operator*(const ModInteger &rhs) { return ModInteger((long long)x * rhs.x % MOD); } void operator*=(const int v) { x = (long long)x * v % MOD; } void operator*=(const ModInteger &rhs) { x = (long long)x * rhs.x % MOD; } ModInteger operator^(int e) { ModInteger res = ModInteger(1), a = *this; for (; e; e >>= 1, a *= a) if (e & 1) res *= a; return res; } void operator^=(int e) { ModInteger res = ModInteger(1), a = *this; for (; e; e >>= 1, a *= a) if (e & 1) res *= a; x = res.x; } ModInteger operator/(const int v) { return ModInteger((long long)x * (ModInteger(v) ^ (MOD - 2)).getValue() % MOD); } ModInteger operator/(const ModInteger &rhs) { ModInteger a = rhs; return ModInteger((long long)x * (a ^ (MOD - 2)).getValue() % MOD); } void operator/=(const int v) { x = (long long)x * (ModInteger(v) ^ (MOD - 2)).getValue() % MOD; } void operator/=(const ModInteger &rhs) { ModInteger a = rhs; x = (long long)x * (a ^ (MOD - 2)).getValue() % MOD; } }; const int MAXN = 4096; ModInteger<> fact[MAXN]; int n, w, b; ModInteger<> calc(int n, int m) { if (n > m) return ModInteger<>(0); return fact[m - 1] / fact[n - 1] / fact[m - n]; } int main() { fact[0] = ModInteger<>(1); for (int i = (1); i < (MAXN); i++) fact[i] = fact[i - 1] * i; scanf("%d%d%d", &n, &w, &b); ModInteger<> res = ModInteger<>(0); for (int i = (2); i < (n); i++) res += calc(i, w) * calc(n - i, b) * (i - 1); res *= fact[w] * fact[b]; printf("%d\n", res.getValue()); return 0; }
#include <bits/stdc++.h> using namespace std; const int mo = 1e9 + 9; int N, W, B; long long POW(long long base, int exp) { if (!exp) return 1; if (exp & 1) return POW(base, exp - 1) * base % mo; long long tmp(POW(base, exp >> 1)); return tmp * tmp % mo; } long long f(int x) { long long ret(1); for (int i = 2; i <= x; i++) ret *= i, ret %= mo; return ret; } long long C(int n, int m) { return f(n) * POW(f(m) * f(n - m) % mo, mo - 2) % mo; } int main() { scanf("%d%d%d", &N, &W, &B); printf("%I64d\n", f(W) * f(B) % mo * (W - 1) % mo * C(W + B - 3, N - 3) % mo); return 0; }
#include <bits/stdc++.h> long long f[200001], C[4001][4001]; int main() { int n, w, b; scanf("%d%d%d", &n, &w, &b); C[0][0] = 1; for (int i = 1; i <= 4000; ++i) for (int j = 0; j <= 4000; ++j) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= 1000000009) C[i][j] -= 1000000009; } f[0] = 1; for (int i = 1; i <= 200000; i++) f[i] = (f[i - 1] * i) % 1000000009; long long ans = 0; for (int i = 2; i < n; ++i) for (int j = i; j < n; ++j) { int bad_days = j - i + 1; int good_days = n - bad_days; (ans += (((((C[w - 1][good_days - 1] * C[b - 1][bad_days - 1]) % 1000000009) * f[w]) % 1000000009) * f[b]) % 1000000009) %= 1000000009; } printf("%I64d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; int C[8001][6001], mo = 1e9 + 9, n, w, b, A[8001], m, I[8001]; int main() { scanf("%d%d%d", &n, &b, &w); for (int i = 0; i <= w + b; i++) { C[i][0] = 1; for (int j = 1; j <= n; j++) C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % mo; } I[0] = 1; for (int i = 1; i <= w + b; i++) I[i] = 1ll * i * I[i - 1] % mo; m = max(w, b); for (int i = 1; i <= n; i++) A[i] = 1ll * C[w - 1][i - 1] * I[w] % mo; int ans = 0; for (int i = 1; i <= n; i++) for (int j = 1; j <= n - i - 1; j++) ans = (ans + 1ll * I[b] * C[b - 1][i + j - 1] % mo * A[n - i - j]) % mo; cout << ans << endl; return 0; }
#include <bits/stdc++.h> #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") #pragma GCC target("sse,sse2,sse3,ssse3,abm,mmx,tune=native") using namespace std; mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); inline void boostIO() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); cout << fixed << setprecision(10); } bool isPrime(int x) { if (x <= 4 || x % 2 == 0 || x % 3 == 0) return x == 2 || x == 3; for (int i = 5; i * i <= x; i += 6) if (x % i == 0 || x % (i + 2) == 0) return 0; return 1; } long long int gcd(long long int a, long long int b) { return b ? gcd(b, a % b) : a; } long long int lcm(long long int a, long long int b) { return a * b / gcd(a, b); } long long Mod = 1e9 + 9; long long inf = 1e9; long long Pow(long long a, long long b) { if (b == 0) return 1; long long c = Pow(a, b / 2); c = c * c % Mod; if (b % 2 == 1) c = c * a % Mod; return c; } long long fac[1000001]; long long d(long long v) { return Pow(v, Mod - 2); } long long CC(long long n, long long k) { return fac[n] * d(fac[n - k]) % Mod * d(fac[k]) % Mod; } int32_t main() { boostIO(); fac[0] = 1; for (long long i = 1; i <= 1000000; ++i) { fac[i] = fac[i - 1] * i % Mod; } long long n, w, b; cin >> n >> w >> b; long long ans = 0; for (long long i = 1; i <= w - 1; ++i) { long long cuts = n - 3; long long left = i - 1; long long mid = b - 1; long long right = w - i - 1; long long P = left + mid + right; ans += fac[w] * fac[b] % Mod * CC(P, cuts) % Mod; ans %= Mod; } cerr << "ans = "; cout << ans << '\n'; }
#include <bits/stdc++.h> using namespace std; const int N = 4000 + 5, mod = 1000000009; int n, x, y; long long P[N], d[N][N]; int main() { scanf("%d", &n); scanf("%d", &x); scanf("%d", &y); for (int i = 0; i <= max(x, y); i++) d[i][0] = 1; for (int i = 1; i <= max(x, y); i++) for (int j = 1; j <= min(n, i); j++) d[i][j] = (d[i - 1][j] + d[i - 1][j - 1]) % mod; P[0] = 1; for (int i = 1; i <= max(x, y); i++) P[i] = (P[i - 1] * i) % mod; long long ans = 0; for (int l = 2; l <= n - 1; l++) for (int r = l; r <= n - 1; r++) ans = (ans + (d[y - 1][r - l] * d[x - 1][n - (r - l + 2)]) % mod) % mod; ans = ans * ((P[x] * P[y]) % mod) % mod; printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; long long n, w, b, ans, jc[4005], inv[4005], mod = 1e9 + 9; long long C(long long n, long long m) { return jc[n] * inv[m] % mod * inv[n - m] % mod; } signed main() { scanf("%lld%lld%lld", &n, &w, &b); jc[0] = 1; for (long long i = 1; i <= 4002; i++) jc[i] = i * jc[i - 1] % mod; inv[0] = inv[1] = 1; for (long long i = 2; i <= 4002; i++) inv[i] = mod - (mod / i) * inv[mod % i] % mod; for (long long i = 1; i <= 4002; i++) inv[i] = inv[i - 1] * inv[i] % mod; for (long long i = 1; i <= b; i++) if (n - i >= 2 && n - i <= w) ans = (ans + (n - i - 1) * C(b - 1, i - 1) % mod * C(w - 1, n - i - 1) % mod) % mod; ans = (ans * jc[w] % mod * jc[b] % mod) % mod; printf("%lld", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int mod = 1000000009; const int N = 4000 + 11; int n, w, b, inv[N][2], mul[N]; long long ans; inline int P(int n) { return mul[n]; } inline int C(int n, int m) { return mul[n] * (long long)inv[m][1] % mod * inv[n - m][1] % mod; } int main(int argc, char **argv) { inv[0][1] = mul[0] = 1; inv[1][0] = inv[1][1] = mul[1] = 1; for (int i = 2; i < N; ++i) inv[i][0] = -inv[mod % i][0] * (long long)(mod / i) % mod, inv[i][1] = inv[i - 1][1] * (long long)inv[i][0] % mod, mul[i] = mul[i - 1] * (long long)i % mod; scanf("%d%d%d", &n, &w, &b); for (int i = 1; i <= w && i <= n; ++i) for (int j = max(1, n - w); i + j < n && j <= b; ++j) ans = (ans + C(b - 1, j - 1) * (long long)C(w - 1, n - j - 1)) % mod; ans = ans * P(w) % mod * P(b) % mod; printf("%d\n", (ans + mod) % mod); return 0; }
#include <bits/stdc++.h> using namespace std; int C[8020][8020]; int f[8020]; void init() { for (int i = 0; i < 8020; ++i) { C[i][0] = C[i][i] = 1; for (int j = 1; j < i; ++j) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= 1000000009) C[i][j] -= 1000000009; } } f[0] = 1; for (int i = 1; i < 8020; ++i) f[i] = 1LL * f[i - 1] * i % 1000000009; } int n, w, b; int main() { init(); cin >> n >> w >> b; int ans = 0; for (int i = 1; i <= w - 1; ++i) { ans += 1LL * C[w + b - 3][n - 3] * C[w][i] % 1000000009 * f[i] % 1000000009 * f[b] % 1000000009 * f[w - i] % 1000000009; if (ans >= 1000000009) ans -= 1000000009; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 4010; const long long M = 1000000009; int main(int argc, char *argv[]) { vector<long long> A(1, 1); for (int n_ = (MAXN), i = 0; i < n_; ++i) A.push_back(A.back() * (i + 1) % M); vector<vector<long long> > C(MAXN, vector<long long>(MAXN)); for (int n_ = (MAXN), i = 0; i < n_; ++i) for (int n_ = (i + 1), j = 0; j < n_; ++j) { if (i == j || j == 0) C[i][j] = 1; else C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % M; } long long N, W, B; cin >> N >> W >> B; long long ans = 0; for (int n_ = (N + 1), a = 0; a < n_; ++a) { int b = N - a; if (a && a <= B && b && b <= W) { ans = (ans + C[B - 1][a - 1] * A[B] % M * C[W - 1][b - 1] % M * A[W] % M * (b - 1)) % M; } } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = 1e9; const double eps = 1e-9; const double INF = inf; const double EPS = eps; int dx[4] = {1, -1, 0, 0}; int dy[4] = {0, 0, 1, -1}; int N[2][1100 * 1100 * 4]; long long T[110000]; int V[110000]; int main() { int x, y, n, q, a, b, c, d, bb, it; int i, j, k, nx, ny; char ch; scanf("%d%d", &n, &b); for (i = 0; i <= b; i++) for (j = 0; j <= b; j++) for (k = 0; k < 4; k++) { nx = i + dx[k], ny = j + dy[k]; nx = max(nx, 0), nx = min(nx, b); ny = max(ny, 0), ny = min(ny, b); N[0][(i * (b + 1) + j) * 4 + k] = (nx * (b + 1) + ny) * 4 + k; } for (i = 0; i < n; i++) { scanf("%d%d%d%d", &a, &bb, &c, &d); assert(a != c || bb != d); int len = abs(a - c) + abs(bb - d); for (it = 0; it < 4; it++) if (c == a + len * dx[it] && d == bb + len * dy[it]) { for (j = 0; j <= len; j++) { x = a + j * dx[it], y = bb + j * dy[it]; int id = (x * (b + 1) + y) * 4; for (k = 0; k < 4; k++) { N[0][id + k] = N[0][id + it]; } } break; } } scanf("%d", &q); for (i = 0; i < q; i++) { scanf("%d%d %c %I64d", &x, &y, &ch, &T[i]); V[i] = (x * (b + 1) + y) * 4; if (ch == 'L') V[i]++; if (ch == 'U') V[i] += 2; if (ch == 'D') V[i] += 3; } for (it = 0; it < 55; it++) { for (i = 0; i < q; i++) if (T[i] & (1ll << it)) V[i] = N[0][V[i]]; for (j = 0; j < (b + 1) * (b + 1) * 4; j++) N[1][j] = N[0][N[0][j]]; memcpy(N[0], N[1], sizeof(N[0])); } for (i = 0; i < q; i++) printf("%d %d\n", V[i] / (4 * (b + 1)), (V[i] / 4) % (b + 1)); ; return 0; }
#include <bits/stdc++.h> #pragma comment(linker, "/STACK:1000000000") using namespace std; const double pi = acos(-1.0); const int size = 1010; const int px[] = {1, 0, -1, 0}; const int py[] = {0, 1, 0, -1}; const int mdeg = 12; const int onelvl = 20; int ways[size][size]; int n, b; int ans[mdeg][size * size * 4]; inline int dirts(int x, int y, int d) { return d * (b + 1) * (b + 1) + x * (b + 1) + y; } inline void backts(int num, int &x, int &y, int &d) { y = num % (b + 1); num /= b + 1; x = num % (b + 1); num /= b + 1; d = num; } int main() { scanf("%d%d", &n, &b); for (int i = 0; i <= b; i++) for (int j = 0; j <= b; j++) ways[i][j] = -1; int xs1, xs2, ys1, ys2; for (int i = 0; i < n; i++) { scanf("%d%d%d%d", &xs1, &ys1, &xs2, &ys2); int len = abs(xs1 - xs2) + abs(ys1 - ys2); int dir = -1; for (int j = 0; j < 4; j++) if (xs1 + px[j] * len == xs2 && ys1 + py[j] * len == ys2) dir = j; for (int j = 0; j <= len; j++) ways[xs1 + px[dir] * j][ys1 + py[dir] * j] = dir; } int hx, hy, hd; for (int i = 0; i <= b; i++) for (int j = 0; j <= b; j++) { for (int k = 0; k < 4; k++) { if (ways[i][j] == -1) { hx = i + px[k]; hy = j + py[k]; hx = max(0, min(hx, b)); hy = max(0, min(hy, b)); ans[0][dirts(i, j, k)] = dirts(hx, hy, k); } else { hd = ways[i][j]; hx = i + px[hd]; hy = j + py[hd]; hx = max(0, min(hx, b)); hy = max(0, min(hy, b)); ans[0][dirts(i, j, k)] = dirts(hx, hy, hd); } } } for (int lvl = 1; lvl < mdeg; lvl++) { for (int i = 0; i <= b; i++) for (int j = 0; j <= b; j++) for (int k = 0; k < 4; k++) { int num = dirts(i, j, k); for (int hp = 0; hp < onelvl; hp++) num = ans[lvl - 1][num]; ans[lvl][dirts(i, j, k)] = num; } } int q, xc, yc; char mdir; long long len; scanf("%d", &q); for (int i = 0; i < q; i++) { scanf("%d%d %c%I64d", &xc, &yc, &mdir, &len); int d = -1; if (mdir == 'R') d = 0; if (mdir == 'U') d = 1; if (mdir == 'L') d = 2; if (mdir == 'D') d = 3; int num = dirts(xc, yc, d); for (int j = 0; j < mdeg; j++) { while (len % onelvl != 0) { num = ans[j][num]; len--; } len /= onelvl; } int xa, ya, da; backts(num, xa, ya, da); printf("%d %d\n", xa, ya); } return 0; }