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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#331076 | #6137. Sub-cycle Graph | Lain | AC ✓ | 175ms | 4248kb | C++23 | 6.2kb | 2024-02-17 23:18:11 | 2024-02-17 23:18:11 |
Judging History
answer
#include "bits/stdc++.h"
using namespace std;
// Source: neal
// Modulo arithmetic
template <const int &MOD>
struct _m_int {
int val;
_m_int(int64_t v = 0) {
if (v < 0) v = v % MOD + MOD;
if (v >= MOD) v %= MOD;
val = int(v);
}
_m_int(uint64_t v) {
if (v >= MOD) v %= MOD;
val = int(v);
}
_m_int(int v) : _m_int(int64_t(v)) {}
_m_int(unsigned v) : _m_int(uint64_t(v)) {}
static int inv_mod(int a, int m = MOD) {
// https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm#Example
int g = m, r = a, x = 0, y = 1;
while (r != 0) {
int q = g / r;
g %= r;
swap(g, r);
x -= q * y;
swap(x, y);
}
return x < 0 ? x + m : x;
}
explicit operator int() const { return val; }
explicit operator unsigned() const { return val; }
explicit operator int64_t() const { return val; }
explicit operator uint64_t() const { return val; }
explicit operator double() const { return val; }
explicit operator long double() const { return val; }
_m_int &operator+=(const _m_int &other) {
val -= MOD - other.val;
if (val < 0) val += MOD;
return *this;
}
_m_int &operator-=(const _m_int &other) {
val -= other.val;
if (val < 0) val += MOD;
return *this;
}
static unsigned fast_mod(uint64_t x, unsigned m = MOD) {
#if !defined(_WIN32) || defined(_WIN64)
return unsigned(x % m);
#endif
// Optimized mod for Codeforces 32-bit machines.
// x must be less than 2^32 * m for this to work, so that x / m fits in an
// unsigned 32-bit int.
unsigned x_high = unsigned(x >> 32), x_low = unsigned(x);
unsigned quot, rem;
asm("divl %4\n" : "=a"(quot), "=d"(rem) : "d"(x_high), "a"(x_low), "r"(m));
return rem;
}
_m_int &operator*=(const _m_int &other) {
val = fast_mod(uint64_t(val) * other.val);
return *this;
}
_m_int &operator/=(const _m_int &other) { return *this *= other.inv(); }
friend _m_int operator+(const _m_int &a, const _m_int &b) {
return _m_int(a) += b;
}
friend _m_int operator-(const _m_int &a, const _m_int &b) {
return _m_int(a) -= b;
}
friend _m_int operator*(const _m_int &a, const _m_int &b) {
return _m_int(a) *= b;
}
friend _m_int operator/(const _m_int &a, const _m_int &b) {
return _m_int(a) /= b;
}
_m_int &operator++() {
val = val == MOD - 1 ? 0 : val + 1;
return *this;
}
_m_int &operator--() {
val = val == 0 ? MOD - 1 : val - 1;
return *this;
}
_m_int operator++(int) {
_m_int before = *this;
++*this;
return before;
}
_m_int operator--(int) {
_m_int before = *this;
--*this;
return before;
}
_m_int operator-() const { return val == 0 ? 0 : MOD - val; }
friend bool operator==(const _m_int &a, const _m_int &b) {
return a.val == b.val;
}
friend bool operator!=(const _m_int &a, const _m_int &b) {
return a.val != b.val;
}
friend bool operator<(const _m_int &a, const _m_int &b) {
return a.val < b.val;
}
friend bool operator>(const _m_int &a, const _m_int &b) {
return a.val > b.val;
}
friend bool operator<=(const _m_int &a, const _m_int &b) {
return a.val <= b.val;
}
friend bool operator>=(const _m_int &a, const _m_int &b) {
return a.val >= b.val;
}
_m_int inv() const { return inv_mod(val); }
_m_int pow(int64_t p) const {
if (p < 0) return inv().pow(-p);
_m_int a = *this, result = 1;
while (p > 0) {
if (p & 1) result *= a;
p >>= 1;
if (p > 0) a *= a;
}
return result;
}
friend ostream &operator<<(ostream &os, const _m_int &m) {
return os << m.val;
}
friend istream &operator>>(istream &is, _m_int &m) {
int64_t x;
is >> x;
m = _m_int(x);
return is;
}
};
const int MOD = 1e9+7;
using mod_int = _m_int<MOD>;
// Source: Based on neal's choose implementation
// Tested on: ABC 235 G
namespace internal_choose {
std::vector<mod_int> factorial = {1}, inv_factorial = {1};
int built_max = 0;
void prepare_factorials(int max) {
if (max <= built_max) return;
max += max / 100;
factorial.resize(max + 1);
inv_factorial.resize(max + 1);
for (int i = built_max + 1; i <= max; i++)
factorial[i] = i * factorial[i - 1];
inv_factorial[max] = factorial[max].inv();
for (int i = max - 1; i > built_max; i--)
inv_factorial[i] = inv_factorial[i + 1] * (i + 1);
built_max = max;
}
}; // namespace internal_choose
mod_int factorial(int n) {
if (n < 0) return 0;
internal_choose::prepare_factorials(n);
return internal_choose::factorial[n];
}
mod_int inv_factorial(int n) {
if (n < 0) return 0;
internal_choose::prepare_factorials(n);
return internal_choose::inv_factorial[n];
}
mod_int choose(int n, int r) {
if (r < 0 || r > n) return 0;
internal_choose::prepare_factorials(n);
return internal_choose::factorial[n] * internal_choose::inv_factorial[n - r] *
internal_choose::inv_factorial[r];
}
mod_int permute(int n, int r) {
if (r < 0 || r > n) return 0;
internal_choose::prepare_factorials(n);
return internal_choose::factorial[n] * internal_choose::inv_factorial[n - r];
}
mod_int inv_choose(int n, int r) {
assert(r >= 0 && r <= n);
internal_choose::prepare_factorials(n);
return internal_choose::inv_factorial[n] * internal_choose::factorial[n - r] *
internal_choose::factorial[r];
}
mod_int inv_permute(int n, int r) {
assert(r >= 0 && r <= n);
internal_choose::prepare_factorials(n);
return internal_choose::inv_factorial[n] * internal_choose::factorial[n - r];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int tt;
cin >> tt;
while(tt--) {
int n, m;
cin >> n >> m;
if (m > n) {
cout << 0 << '\n';
continue;
}
if (m == 0) {
cout << 1 << '\n';
continue;
}
if (n == m) {
cout << factorial(n-1)/2 << '\n';
continue;
}
mod_int ans = 0, prod = 1;
for (int i = 1; i <= n-m; i++) {
prod *= 2*i-1;
ans += choose(n, n-m-i) * factorial(m-i) * choose(m-1, i-1) * choose(m+i, 2*i) * prod;
}
cout << ans << '\n';
}
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 3612kb
input:
3 4 2 4 3 5 3
output:
15 12 90
result:
ok 3 number(s): "15 12 90"
Test #2:
score: 0
Accepted
time: 175ms
memory: 4248kb
input:
17446 3 0 3 1 3 2 3 3 4 0 4 1 4 2 4 3 4 4 5 0 5 1 5 2 5 3 5 4 5 5 6 0 6 1 6 2 6 3 6 4 6 5 6 6 7 0 7 1 7 2 7 3 7 4 7 5 7 6 7 7 8 0 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 9 0 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 9 9 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 11 0 11 1 11 2 11 3 11 4 11 5 11 6 11 7 11...
output:
1 3 3 1 1 6 15 12 3 1 10 45 90 60 12 1 15 105 375 630 360 60 1 21 210 1155 3465 5040 2520 360 1 28 378 2940 13545 35280 45360 20160 2520 1 36 630 6552 42525 170100 393120 453600 181440 20160 1 45 990 13230 114345 643545 2286900 4762800 4989600 1814400 181440 1 55 1485 24750 273735 2047815 10239075 3...
result:
ok 17446 numbers