概率与期望
CF1523E
前面显然期望转换。
考虑最后不满足状态。
钦定i盏灯点亮，那就是 \(\binom{n}{i}\)
然后我要求不满足，那就是每两盏之间要有至少 \(k-1\) 盏，提前减去即可。
注意细节，要提前减去的灯数够用，否则 break，不然会爆 int。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1523E {
bool _1;
static const i32 N = 100005;
static const i32 P = 1000000007;
i32 n, k;
i32 fac[N], inv[N];
bool _2;
i32 inc(i32 x, i32 y) { return (x + y) % P; }
template<typename ...Args>
i32 inc(i32 x, Args ...args) { return inc(x, inc(args...)); }
i32 dec(i32 x, i32 y) { return (x + P - y) % P; }
i32 mul(i32 x, i32 y) { return 1LL * x * y % P; }
template<typename ...Args>
i32 mul(i32 x, Args ...args) { return mul(x, mul(args...)); }
i32 qpow(i32 x, i32 y) {
i32 ans = 1;
for (; y; y >>= 1, x = mul(x, x))
if (y & 1) ans = mul(ans, x);
return ans;
}
void init(i32 n) {
fac[0] = 1;
for (i32 i = 1; i <= n; ++i) fac[i] = mul(fac[i - 1], i);
inv[n] = qpow(fac[n], P - 2);
for (i32 i = n - 1; i >= 0; --i) inv[i] = mul(inv[i + 1], i + 1);
return void();
}
i32 binom(i32 n, i32 m) {
if (n < m || m < 0) return 0;
return mul(fac[n], inv[m], inv[n - m]);
}
i32 f(i32 n, i32 k, i32 i) { return mul(binom(n - (i - 1) * (k - 1), i), qpow(binom(n, i), P - 2)); }
void solve() {
n = read(), k = read();
i32 ans = 1;
for (i32 i = 1; i < n; ++i) {
if ((i - 1) * (k - 1) > n) break;
ans = inc(ans, f(n, k, i));
}
return fprintf(fout, "%d\n", ans), void();
}
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
init(N - 1);
i32 t = read();
i64 Start_Time_Without_Read = clock();
while (t--) solve();
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1523E::main(), 0; }
CF1737E
思考一个人怎么赢。
他必须得向左。
首先一定是吃掉左边连续的向右。
然后此时剩下一堆左的。
在我吃到他们前，他们一定先吃完了，所以是相当于我要吃掉前 \(i-1\) 个。
考虑我去吃的时候，左边重量是前 \(i-1\) 个的重量和减去我左边连续的向右的。
所以前面得有 \(n - \frac{i}{2} - 2\) 个向右的，再强制钦定我必须向左，所以要 \(2^{n - \frac{i}{2} - 1}\)。
记 \(f_i\) 为 \(i\) 胜利的概率。
然后是我后面不能赢，后面至少是 \(2i\) 开始的，所以是 \(1 - \sum_{j\geq2i}f_i\)。
直接倒着做加上前缀\后缀和即可。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1737E {
bool _1;
static const i32 N = 1000005;
static const i32 P = 1000000007;
i32 n, f[N], sum[N], fpow2[N];
bool _2;
i32 inc(i32 x, i32 y) { return (x + y) % P; }
i32 dec(i32 x, i32 y) { return (x + P - y) % P; }
i32 mul(i32 x, i32 y) { return 1LL * x * y % P; }
i32 qpow(i32 x, i32 y) {
i32 ans = 1;
for (; y; y >>= 1, x = mul(x, x))
if (y & 1) ans = mul(ans, x);
return ans;
}
i32 sumf(i32 l, i32 r) {
if (l > r) return 0;
return sum[l] - sum[r + 1];
}
void solve() {
n = read();
sum[n + 1] = 0;
f[n] = 1, sum[n] = 1;
for (i32 i = n - 1; i >= 1; --i) {
// i/2+1 ~ i
i32 l = i + 1, r = std::min(2 * i - 1, n);
f[i] = dec(sum[l], sum[r + 1]);
sum[i] = inc(sum[i + 1], f[i]);
}
for (i32 i = 1; i <= n; ++i)
fprintf(fout, "%d\n", mul(f[i], qpow(fpow2[n - i / 2 - 1], P - 2)));
return void();
}
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
fpow2[0] = 1;
for (i32 i = 1; i < N; ++i)
fpow2[i] = mul(fpow2[i - 1], 2);
i32 t = read();
i64 Start_Time_Without_Read = clock();
while (t--) solve();
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1737E::main(), 0; }
CF1874C
由于拓扑，考虑从后往前做。
设 \(f_i\) 为 \(i\) 到 \(n\) 的答案。
每次显然选 f 值最大的更优。
预处理 \(dp_{i,j}\) 为出度为 \(i\) 的点，选到第 \(j\) 大的概率。
大概写一下， \(dp_{i,1} = \frac{1}{i}, dp_{i,2} = \frac{i-2}{i} \times \frac{1}{i-2}\)。
然后转移很显然了， \(dp_{i,j} = dp_{i-2,j-2} \times \frac{j-2}{i} + dp_{i-2,j-1} \times \frac{i - j}{i}\)。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1874C {
bool _1;
static const i32 N = 5005;
i32 n, m;
double f[N][N], dp[N];
std::vector<i32> e[N];
void init(i32 n) {
f[1][1] = 1, f[2][1] = 0.5;
for (i32 i = 3; i <= n; ++i) {
f[i][1] = 1.0 / i;
for (i32 j = 2; j <= n; ++j)
f[i][j] = 1.0 * (j - 2) / i * f[i - 2][j - 2] + 1.0 * (i - j) / i * f[i - 2][j - 1];
}
return void();
}
void solve() {
n = read(), m = read();
for (i32 i = 1; i <= n; ++i) e[i].clear();
for (i32 i = 1; i <= m; ++i) {
static i32 u, v;
u = read(), v = read();
e[u].eb(v);
}
dp[n] = 1;
for (i32 i = n - 1; i >= 1; --i) {
dp[i] = 0;
std::sort(all(e[i]), [&](const i32 &x, const i32 &y) { return dp[x] > dp[y]; });
for (i32 j = 0; j < size(e[i]); ++j) dp[i] += dp[e[i][j]] * f[size(e[i])][j + 1];
}
fprintf(fout, "%.9lf\n", dp[1]);
return void();
}
bool _2;
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
init(N - 1);
i32 t = read();
i64 Start_Time_Without_Read = clock();
while (t--) solve();
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1874C::main(), 0; }
CF1874D
考虑 \(f_i = 1 + \frac{a_i}{a_i + a_{i + 1}} \times f_{i - 1} + \frac{a_{i + 1}}{a_i + a_{i + 1}} \times f_{i + 1}\)。
化简后， \(a_{i+1}(f_i-f_{i+1}) = a_i(f_{i-1}-f_{i})+a_i+a_{i+1}\)。
差分一下，\(g_i = f_{i-1}-f_i，g_i = \frac{2 \sum_{j<i}a_j}{a_i} + 1\)。
答案就是 \(\sum_i g_i\)。
展开成为 \(2 * \sum_i \frac{1}{a_i} \sum_{j<i} a_j + n\)。
设 \(dp_{i,j}\) 表示我考虑到第 \(i\) 位，和为 \(j\)。
\(dp_{i+1,j+k} = dp_{i,j} + \frac{j}{k}\)。
本来 \(O(n^3)\)，由于显然 \(a_i\) 单调不减， \(k\) 的取值是类似调和级数，复杂度 \(O(n^2 \log n)\)。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1874D {
bool _1;
static const i32 N = 3005;
i32 n, m;
double dp[N][N];
bool _2;
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
n = read(), m = read();
i64 Start_Time_Without_Read = clock();
for (i32 i = 0; i <= n; ++i)
for (i32 j = 0; j <= m; ++j)
dp[i][j] = 1e18;
dp[0][0] = 0;
for (i32 i = 0; i < n; ++i)
for (i32 s = 0; s <= m; ++s)
for (i32 j = 1; s + (n - i) * j <= m; ++j)
chkmin(dp[i + 1][s + j], dp[i][s] + 1.0 * s / j);
fprintf(fout, "%.9lf\n", 2 * dp[n][m] + n);
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1874D::main(), 0; }
CF1295F
有个显然的 dp，记 \(f_{i,j}\) 为考虑到第 \(i\) 位，\(a_i = j\) 的方案。
考虑直接离散，然后根据上面的改。
有个小技巧，把所有区间表示为左闭右开的形式，这样可以拆成很多单位区间。
然后套用上面的 dp,但是在一个单位区间也有可能不同，这时候枚举一个 \(k\)，表示 \([k, i]\) 内的数都在这个单位区间，方案在乘上一个系数即可。
系数的话考虑我有 \(a_{j+1} - a_j\) 个位置，然后由于可以相等，就用插板法，\(\binom{a_{j+1}-a_j+1+(i-k)}{i-k}\)。
由于算的是方案，还得除以总方案。
注意一下区间范围是 long long，组合数直接暴力求。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i64 read() {
i64 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1295F {
bool _1;
static const i32 N = 55;
static const i32 P = 998244353;
i32 n;
i64 l[N], r[N], a[N * 2];
i32 f[N][N * 2];
bool _2;
i32 inc(i32 x, i32 y) { return (x + y) % P; }
i32 dec(i32 x, i32 y) { return (x + P - y) % P; }
i32 mul(i32 x, i32 y) { return 1LL * x * y % P; }
i32 qpow(i32 x, i32 y) {
i32 ans = 1;
for (; y; y >>= 1, x = mul(x, x))
if (y & 1) ans = mul(ans, x);
return ans;
}
i32 binom(i64 n, i32 m) {
if (n < m || m < 0) return 0;
i32 ans = 1;
for (i64 i = n; i > n - m; --i) ans = mul(ans, i % P);
for (i32 i = 1; i <= m; ++i) ans = mul(ans, qpow(i, P - 2));
return ans;
}
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
n = read();
for (i32 i = 1; i <= n; ++i) {
l[i] = read(), r[i] = read() + 1;
a[i * 2 - 1] = l[i], a[i * 2] = r[i];
}
i64 Start_Time_Without_Read = clock();
std::sort(a + 1, a + 2 * n + 1);
i32 m = std::unique(a + 1, a + 2 * n + 1) - a - 1;
for (i32 i = 1; i <= n; ++i) l[i] = std::lower_bound(a + 1, a + m + 1, l[i]) - a;
for (i32 i = 1; i <= n; ++i) r[i] = std::lower_bound(a + 1, a + m + 1, r[i]) - a;
f[0][m] = 1;
for (i32 i = 1; i <= n; ++i)
for (i32 j = 1; j < m; ++j)
for (i32 k = i - 1; k >= 0; --k) {
if (!(l[k + 1] <= j && j + 1 <= r[k + 1])) break;
i32 now = 0;
for (i32 p = j + 1; p <= m; ++p) now = inc(now, f[k][p]);
now = mul(now, binom(a[j + 1] - a[j] - 1 + (i - k), i - k));
f[i][j] = inc(f[i][j], now);
}
i32 ans = 0;
for (i32 i = 1; i < m; ++i) ans = inc(ans, f[n][i]);
for (i32 i = 1; i <= n; ++i) ans = mul(ans, qpow((a[r[i]] - a[l[i]]) % P, P - 2));
fprintf(fout, "%d\n", ans);
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1295F::main(), 0; }
CF1842G
考虑组合意义。
相当于一条 1~\(n+1\) 的链，\(i\) 到 \(i+1\) 有 \(a_i\) 中走法，我可以随机放工具，得到工具可以多 \(v\) 种走法，工具随时使用。
直接 dp,考虑走到第 \(i\) 个点，有 \(j\) 个工具。
-
直接用 \(a_i\) 走， \(dp_{i+1,j}<-dp_{i,j}*a_i\)
-
使用拥有的工具， \(dp_{i+1,j}<-dp_{i,j}*j*v\)
-
新增工具，可以从 \([1,i]\) 中任意一点来， \(dp_{i+1,j+1}<-dp_{i,j}*(m-j)*(i+1)*v\)
最后除去总方案即可。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1842G {
bool _1;
static const i32 N = 5005;
static const i32 P = 1000000007;
i32 n, m, v;
i32 a[N];
i32 dp[N][N];
i32 fpown[N];
bool _2;
i32 inc(i32 x, i32 y) { return (x + y) % P; }
template<typename ...Args>
i32 inc(i32 x, Args ...args) { return inc(x, inc(args...)); }
i32 dec(i32 x, i32 y) { return (x + P - y) % P; }
i32 mul(i32 x, i32 y) { return 1LL * x * y % P; }
template<typename ...Args>
i32 mul(i32 x, Args ...args) { return mul(x, mul(args...)); }
i32 qpow(i32 x, i32 y) {
i32 ans = 1;
for (; y; y >>= 1, x = mul(x, x))
if (y & 1) ans = mul(ans, x);
return ans;
}
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
n = read(), m = read(), v = read();
for (i32 i = 1; i <= n; ++i) a[i] = read();
i64 Start_Time_Without_Read = clock();
fpown[0] = 1;
for (i32 i = 1; i <= std::min(n, m); ++i) fpown[i] = mul(fpown[i - 1], n);
dp[1][0] = 1;
for (i32 i = 1; i <= n; ++i)
for (i32 j = 0; j <= std::min(m, i); ++j) {
dp[i + 1][j] = inc(dp[i + 1][j], mul(dp[i][j], a[i]));
dp[i + 1][j] = inc(dp[i + 1][j], mul(dp[i][j], j, v));
dp[i + 1][j + 1] = inc(dp[i + 1][j + 1], mul(dp[i][j], i, m - j, v));
}
i32 ans = 0;
for (i32 i = 0; i <= std::min(n, m); ++i)
ans = inc(ans, mul(dp[n + 1][i], qpow(fpown[i], P - 2)));
fprintf(fout, "%d\n", ans);
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1842G::main(), 0; }
CF1842H
对每个 \(x_i\) 先减 \(0.5\)，限制变成 \(\geq0\) 或 \(\leq0\)
给每个 \(x_i\) 取绝对值，显然对于所有条件，我只需要考虑绝对值更大的数他的正负。
设 \(dp_S\) 为当前考虑集合 \(S\) 的数，是合法的方案书。
每次枚举一个加入的数，由于我们钦定从大到小加入，直接判一下它取正负是否符合条件加上方案即可。
由于钦定顺序，最后除总方案多除 \(n!\) 即可。
#pragma region
#include <bits/stdc++.h>
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define ep emplace
#define eb emplace_back
#define all(x) x.begin(), x.end()
FILE *fin, *fout, *ferr;
i32 read() {
i32 t = 0, f = 0;
char ch = fgetc(fin);
for (; !isdigit(ch); ch = fgetc(fin)) f ^= (ch == '-');
for (; isdigit(ch); ch = fgetc(fin)) t = (t << 1) + (t << 3) + (ch ^ 48);
return f ? -t : t;
}
template<typename T1, typename T2>
constexpr bool chkmax(T1 &a, T2 b) { return a > b ? false : (a = b, true); }
template<typename T1, typename T2>
constexpr bool chkmin(T1 &a, T2 b) { return a > b ? (a = b, true) : false; }
#pragma endregion
namespace Solution_Of_CF1842H {
bool _1;
static const i32 N = 20;
static const i32 P = 998244353;
i32 n, m;
i32 a[N][2], f[1 << N];
bool _2;
i32 inc(i32 x, i32 y) { return (x + y) % P; }
template<typename ...Args>
i32 inc(i32 x, Args ...args) { return inc(x, inc(args...)); }
i32 dec(i32 x, i32 y) { return (x + P - y) % P; }
i32 mul(i32 x, i32 y) { return 1LL * x * y % P; }
template<typename ...Args>
i32 mul(i32 x, Args ...args) { return mul(x, mul(args...)); }
i32 qpow(i32 x, i32 y) {
i32 ans = 1;
for (; y; y >>= 1, x = mul(x, x))
if (y & 1) ans = mul(ans, x);
return ans;
}
void main() {
fin = stdin, fout = stdout, ferr = stderr;
fprintf(ferr, "This code use %.2lf MB memory\n", 1.0 * (&_1 - &_2) / 1024 / 1024);
n = read(), m = read();
for (i32 i = 1; i <= m; ++i) {
static i32 op, u, v;
op = read();
u = read() - 1, v = read() - 1;
a[u][op] |= 1u << v, a[v][op] |= 1u << u;
}
i64 Start_Time_Without_Read = clock();
f[0] = 1;
for (i32 S = 0; S < (1 << n); ++S)
for (i32 i = 0; i < n; ++i)
if (S >> i & 1)
for (i32 j = 0; j < 2; ++j)
if (!(a[i][j ^ 1] & S))
f[S] = inc(f[S], f[S ^ (1u << i)]);
i32 ans = f[(1u << n) - 1];
for (i32 i = 1; i <= n; ++i)
ans = mul(ans, qpow(i, P - 2));
ans = mul(ans, qpow(1 << n, P - 2));
fprintf(fout, "%d\n", ans);
i64 End_Time_Without_Read = clock();
fprintf(ferr, "This code use %lld ms time\n", End_Time_Without_Read - Start_Time_Without_Read);
return void();
}
}
signed main() { return Solution_Of_CF1842H::main(), 0; }
本文来自博客园，作者：xxcxu，转载请注明原文链接：https://www.cnblogs.com/Maraschino/p/17783286.html
