#include <bits/stdc++.h>
using namespace std;
template <typename T> T mod_inv_in_range(T a, T m) {
// assert(0 <= a && a < m);
T x = a, y = m;
// coeff of a in x and y
T vx = 1, vy = 0;
while (x) {
T k = y / x;
y %= x;
vy -= k * vx;
std::swap(x, y);
std::swap(vx, vy);
}
assert(y == 1);
return vy < 0 ? m + vy : vy;
}
template <typename T> struct extended_gcd_result {
T gcd;
T coeff_a, coeff_b;
};
template <typename T> extended_gcd_result<T> extended_gcd(T a, T b) {
T x = a, y = b;
// coeff of a and b in x and y
T ax = 1, ay = 0;
T bx = 0, by = 1;
while (x) {
T k = y / x;
y %= x;
ay -= k * ax;
by -= k * bx;
std::swap(x, y);
std::swap(ax, ay);
std::swap(bx, by);
}
return {y, ay, by};
}
template <typename T> T mod_inv(T a, T m) {
a %= m;
a = a < 0 ? a + m : a;
return mod_inv_in_range(a, m);
}
template <int MOD_> struct modnum {
static constexpr int MOD = MOD_;
static_assert(MOD_ > 0, "MOD must be positive");
private:
int v;
public:
modnum() : v(0) {}
modnum(int64_t v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; }
explicit operator int() const { return v; }
friend std::ostream& operator << (std::ostream& out, const modnum& n) { return out << int(n); }
friend std::istream& operator >> (std::istream& in, modnum& n) { int64_t v_; in >> v_; n = modnum(v_); return in; }
friend bool operator == (const modnum& a, const modnum& b) { return a.v == b.v; }
friend bool operator != (const modnum& a, const modnum& b) { return a.v != b.v; }
modnum inv() const {
modnum res;
res.v = mod_inv_in_range(v, MOD);
return res;
}
friend modnum inv(const modnum& m) { return m.inv(); }
modnum neg() const {
modnum res;
res.v = v ? MOD-v : 0;
return res;
}
friend modnum neg(const modnum& m) { return m.neg(); }
modnum operator- () const {
return neg();
}
modnum operator+ () const {
return modnum(*this);
}
modnum& operator ++ () {
v ++;
if (v == MOD) v = 0;
return *this;
}
modnum& operator -- () {
if (v == 0) v = MOD;
v --;
return *this;
}
modnum& operator += (const modnum& o) {
v -= MOD-o.v;
v = (v < 0) ? v + MOD : v;
return *this;
}
modnum& operator -= (const modnum& o) {
v -= o.v;
v = (v < 0) ? v + MOD : v;
return *this;
}
modnum& operator *= (const modnum& o) {
v = int(int64_t(v) * int64_t(o.v) % MOD);
return *this;
}
modnum& operator /= (const modnum& o) {
return *this *= o.inv();
}
friend modnum operator ++ (modnum& a, int) { modnum r = a; ++a; return r; }
friend modnum operator -- (modnum& a, int) { modnum r = a; --a; return r; }
friend modnum operator + (const modnum& a, const modnum& b) { return modnum(a) += b; }
friend modnum operator - (const modnum& a, const modnum& b) { return modnum(a) -= b; }
friend modnum operator * (const modnum& a, const modnum& b) { return modnum(a) *= b; }
friend modnum operator / (const modnum& a, const modnum& b) { return modnum(a) /= b; }
};
template <typename T> T pow(T a, long long b) {
assert(b >= 0);
T r = 1; while (b) { if (b & 1) r *= a; b >>= 1; a *= a; } return r;
}
template <typename tag> struct dynamic_modnum {
private:
#if __cpp_inline_variables >= 201606
// C++17 and up
inline static int MOD_ = 0;
inline static uint64_t BARRETT_M = 0;
#else
// NB: these must be initialized out of the class by hand:
// static int dynamic_modnum<tag>::MOD = 0;
// static int dynamic_modnum<tag>::BARRETT_M = 0;
static int MOD_;
static uint64_t BARRETT_M;
#endif
public:
// Make only the const-reference public, to force the use of set_mod
static constexpr int const& MOD = MOD_;
// Barret reduction taken from KACTL:
/**
* Author: Simon Lindholm
* Date: 2020-05-30
* License: CC0
* Source: https://en.wikipedia.org/wiki/Barrett_reduction
* Description: Compute $a \% b$ about 5 times faster than usual, where $b$ is constant but not known at compile time.
* Returns a value congruent to $a \pmod b$ in the range $[0, 2b)$.
* Status: proven correct, stress-tested
* Measured as having 4 times lower latency, and 8 times higher throughput, see stress-test.
* Details:
* More precisely, it can be proven that the result equals 0 only if $a = 0$,
* and otherwise lies in $[1, (1 + a/2^64) * b)$.
*/
static void set_mod(int mod) {
assert(mod > 0);
MOD_ = mod;
BARRETT_M = (uint64_t(-1) / MOD);
}
static uint32_t barrett_reduce_partial(uint64_t a) {
return uint32_t(a - uint64_t((__uint128_t(BARRETT_M) * a) >> 64) * MOD);
}
static int barrett_reduce(uint64_t a) {
int32_t res = int32_t(barrett_reduce_partial(a) - MOD);
return (res < 0) ? res + MOD : res;
}
struct mod_reader {
friend std::istream& operator >> (std::istream& i, mod_reader) {
int mod; i >> mod;
dynamic_modnum::set_mod(mod);
return i;
}
};
static mod_reader MOD_READER() {
return mod_reader();
}
private:
int v;
public:
dynamic_modnum() : v(0) {}
dynamic_modnum(int64_t v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; }
explicit operator int() const { return v; }
friend std::ostream& operator << (std::ostream& out, const dynamic_modnum& n) { return out << int(n); }
friend std::istream& operator >> (std::istream& in, dynamic_modnum& n) { int64_t v_; in >> v_; n = dynamic_modnum(v_); return in; }
friend bool operator == (const dynamic_modnum& a, const dynamic_modnum& b) { return a.v == b.v; }
friend bool operator != (const dynamic_modnum& a, const dynamic_modnum& b) { return a.v != b.v; }
dynamic_modnum inv() const {
dynamic_modnum res;
res.v = mod_inv_in_range(v, MOD);
return res;
}
friend dynamic_modnum inv(const dynamic_modnum& m) { return m.inv(); }
dynamic_modnum neg() const {
dynamic_modnum res;
res.v = v ? MOD-v : 0;
return res;
}
friend dynamic_modnum neg(const dynamic_modnum& m) { return m.neg(); }
dynamic_modnum operator- () const {
return neg();
}
dynamic_modnum operator+ () const {
return dynamic_modnum(*this);
}
dynamic_modnum& operator ++ () {
v ++;
if (v == MOD) v = 0;
return *this;
}
dynamic_modnum& operator -- () {
if (v == 0) v = MOD;
v --;
return *this;
}
dynamic_modnum& operator += (const dynamic_modnum& o) {
v -= MOD-o.v;
v = (v < 0) ? v + MOD : v;
return *this;
}
dynamic_modnum& operator -= (const dynamic_modnum& o) {
v -= o.v;
v = (v < 0) ? v + MOD : v;
return *this;
}
dynamic_modnum& operator *= (const dynamic_modnum& o) {
v = barrett_reduce(int64_t(v) * int64_t(o.v));
return *this;
}
dynamic_modnum& operator /= (const dynamic_modnum& o) {
return *this *= o.inv();
}
friend dynamic_modnum operator ++ (dynamic_modnum& a, int) { dynamic_modnum r = a; ++a; return r; }
friend dynamic_modnum operator -- (dynamic_modnum& a, int) { dynamic_modnum r = a; --a; return r; }
friend dynamic_modnum operator + (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) += b; }
friend dynamic_modnum operator - (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) -= b; }
friend dynamic_modnum operator * (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) *= b; }
friend dynamic_modnum operator / (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) /= b; }
};
int main(){
ios_base::sync_with_stdio(false), cin.tie(nullptr);
int A, B, C, P;
cin >> A >> B >> C >> P;
struct tag;
using num = dynamic_modnum<tag>;
num::set_mod(P);
int M = A * B;
vector<num> fact(M+1), ifact(M+1);
fact[0] = 1;
for(int i = 1; i <= M; i++){
fact[i] = fact[i-1] * i;
}
ifact[M] = 1 / fact[M];
for(int i = M-1; i >= 0; i--){
ifact[i] = ifact[i+1] * (i+1);
}
int cnt = 0;
for(int x = 1; x <= A; x++){
for(int y = 1; y <= B; y++){
if(x + y - 1 <= C){
cnt += 1;
}
}
}
cout << cnt << ' ';
num ans = fact[cnt];
for(int x = 1; x <= A; x++){
ans *= ifact[x+B-1] * fact[x-1];
}
cout << (ans * ans);
cout << '\n';
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 | #include <bits/stdc++.h> using namespace std; template <typename T> T mod_inv_in_range(T a, T m) { // assert(0 <= a && a < m); T x = a, y = m; // coeff of a in x and y T vx = 1, vy = 0; while (x) { T k = y / x; y %= x; vy -= k * vx; std::swap(x, y); std::swap(vx, vy); } assert(y == 1); return vy < 0 ? m + vy : vy; } template <typename T> struct extended_gcd_result { T gcd; T coeff_a, coeff_b; }; template <typename T> extended_gcd_result<T> extended_gcd(T a, T b) { T x = a, y = b; // coeff of a and b in x and y T ax = 1, ay = 0; T bx = 0, by = 1; while (x) { T k = y / x; y %= x; ay -= k * ax; by -= k * bx; std::swap(x, y); std::swap(ax, ay); std::swap(bx, by); } return {y, ay, by}; } template <typename T> T mod_inv(T a, T m) { a %= m; a = a < 0 ? a + m : a; return mod_inv_in_range(a, m); } template <int MOD_> struct modnum { static constexpr int MOD = MOD_; static_assert(MOD_ > 0, "MOD must be positive"); private: int v; public: modnum() : v(0) {} modnum(int64_t v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; } explicit operator int() const { return v; } friend std::ostream& operator << (std::ostream& out, const modnum& n) { return out << int(n); } friend std::istream& operator >> (std::istream& in, modnum& n) { int64_t v_; in >> v_; n = modnum(v_); return in; } friend bool operator == (const modnum& a, const modnum& b) { return a.v == b.v; } friend bool operator != (const modnum& a, const modnum& b) { return a.v != b.v; } modnum inv() const { modnum res; res.v = mod_inv_in_range(v, MOD); return res; } friend modnum inv(const modnum& m) { return m.inv(); } modnum neg() const { modnum res; res.v = v ? MOD-v : 0; return res; } friend modnum neg(const modnum& m) { return m.neg(); } modnum operator- () const { return neg(); } modnum operator+ () const { return modnum(*this); } modnum& operator ++ () { v ++; if (v == MOD) v = 0; return *this; } modnum& operator -- () { if (v == 0) v = MOD; v --; return *this; } modnum& operator += (const modnum& o) { v -= MOD-o.v; v = (v < 0) ? v + MOD : v; return *this; } modnum& operator -= (const modnum& o) { v -= o.v; v = (v < 0) ? v + MOD : v; return *this; } modnum& operator *= (const modnum& o) { v = int(int64_t(v) * int64_t(o.v) % MOD); return *this; } modnum& operator /= (const modnum& o) { return *this *= o.inv(); } friend modnum operator ++ (modnum& a, int) { modnum r = a; ++a; return r; } friend modnum operator -- (modnum& a, int) { modnum r = a; --a; return r; } friend modnum operator + (const modnum& a, const modnum& b) { return modnum(a) += b; } friend modnum operator - (const modnum& a, const modnum& b) { return modnum(a) -= b; } friend modnum operator * (const modnum& a, const modnum& b) { return modnum(a) *= b; } friend modnum operator / (const modnum& a, const modnum& b) { return modnum(a) /= b; } }; template <typename T> T pow(T a, long long b) { assert(b >= 0); T r = 1; while (b) { if (b & 1) r *= a; b >>= 1; a *= a; } return r; } template <typename tag> struct dynamic_modnum { private: #if __cpp_inline_variables >= 201606 // C++17 and up inline static int MOD_ = 0; inline static uint64_t BARRETT_M = 0; #else // NB: these must be initialized out of the class by hand: // static int dynamic_modnum<tag>::MOD = 0; // static int dynamic_modnum<tag>::BARRETT_M = 0; static int MOD_; static uint64_t BARRETT_M; #endif public: // Make only the const-reference public, to force the use of set_mod static constexpr int const& MOD = MOD_; // Barret reduction taken from KACTL: /** * Author: Simon Lindholm * Date: 2020-05-30 * License: CC0 * Source: https://en.wikipedia.org/wiki/Barrett_reduction * Description: Compute $a \% b$ about 5 times faster than usual, where $b$ is constant but not known at compile time. * Returns a value congruent to $a \pmod b$ in the range $[0, 2b)$. * Status: proven correct, stress-tested * Measured as having 4 times lower latency, and 8 times higher throughput, see stress-test. * Details: * More precisely, it can be proven that the result equals 0 only if $a = 0$, * and otherwise lies in $[1, (1 + a/2^64) * b)$. */ static void set_mod(int mod) { assert(mod > 0); MOD_ = mod; BARRETT_M = (uint64_t(-1) / MOD); } static uint32_t barrett_reduce_partial(uint64_t a) { return uint32_t(a - uint64_t((__uint128_t(BARRETT_M) * a) >> 64) * MOD); } static int barrett_reduce(uint64_t a) { int32_t res = int32_t(barrett_reduce_partial(a) - MOD); return (res < 0) ? res + MOD : res; } struct mod_reader { friend std::istream& operator >> (std::istream& i, mod_reader) { int mod; i >> mod; dynamic_modnum::set_mod(mod); return i; } }; static mod_reader MOD_READER() { return mod_reader(); } private: int v; public: dynamic_modnum() : v(0) {} dynamic_modnum(int64_t v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; } explicit operator int() const { return v; } friend std::ostream& operator << (std::ostream& out, const dynamic_modnum& n) { return out << int(n); } friend std::istream& operator >> (std::istream& in, dynamic_modnum& n) { int64_t v_; in >> v_; n = dynamic_modnum(v_); return in; } friend bool operator == (const dynamic_modnum& a, const dynamic_modnum& b) { return a.v == b.v; } friend bool operator != (const dynamic_modnum& a, const dynamic_modnum& b) { return a.v != b.v; } dynamic_modnum inv() const { dynamic_modnum res; res.v = mod_inv_in_range(v, MOD); return res; } friend dynamic_modnum inv(const dynamic_modnum& m) { return m.inv(); } dynamic_modnum neg() const { dynamic_modnum res; res.v = v ? MOD-v : 0; return res; } friend dynamic_modnum neg(const dynamic_modnum& m) { return m.neg(); } dynamic_modnum operator- () const { return neg(); } dynamic_modnum operator+ () const { return dynamic_modnum(*this); } dynamic_modnum& operator ++ () { v ++; if (v == MOD) v = 0; return *this; } dynamic_modnum& operator -- () { if (v == 0) v = MOD; v --; return *this; } dynamic_modnum& operator += (const dynamic_modnum& o) { v -= MOD-o.v; v = (v < 0) ? v + MOD : v; return *this; } dynamic_modnum& operator -= (const dynamic_modnum& o) { v -= o.v; v = (v < 0) ? v + MOD : v; return *this; } dynamic_modnum& operator *= (const dynamic_modnum& o) { v = barrett_reduce(int64_t(v) * int64_t(o.v)); return *this; } dynamic_modnum& operator /= (const dynamic_modnum& o) { return *this *= o.inv(); } friend dynamic_modnum operator ++ (dynamic_modnum& a, int) { dynamic_modnum r = a; ++a; return r; } friend dynamic_modnum operator -- (dynamic_modnum& a, int) { dynamic_modnum r = a; --a; return r; } friend dynamic_modnum operator + (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) += b; } friend dynamic_modnum operator - (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) -= b; } friend dynamic_modnum operator * (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) *= b; } friend dynamic_modnum operator / (const dynamic_modnum& a, const dynamic_modnum& b) { return dynamic_modnum(a) /= b; } }; int main(){ ios_base::sync_with_stdio(false), cin.tie(nullptr); int A, B, C, P; cin >> A >> B >> C >> P; struct tag; using num = dynamic_modnum<tag>; num::set_mod(P); int M = A * B; vector<num> fact(M+1), ifact(M+1); fact[0] = 1; for(int i = 1; i <= M; i++){ fact[i] = fact[i-1] * i; } ifact[M] = 1 / fact[M]; for(int i = M-1; i >= 0; i--){ ifact[i] = ifact[i+1] * (i+1); } int cnt = 0; for(int x = 1; x <= A; x++){ for(int y = 1; y <= B; y++){ if(x + y - 1 <= C){ cnt += 1; } } } cout << cnt << ' '; num ans = fact[cnt]; for(int x = 1; x <= A; x++){ ans *= ifact[x+B-1] * fact[x-1]; } cout << (ans * ans); cout << '\n'; } |
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