QOJ.ac
QOJ
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 |
---|---|---|---|---|---|---|---|---|---|
#824994 | #9778. Brotato | ucup-team4474# | WA | 1ms | 8260kb | C++20 | 4.4kb | 2024-12-21 16:52:46 | 2024-12-21 16:52:51 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
using i128 = __int128_t;
bool Memory_begin;
template <int mod>
unsigned int down(unsigned int x)
{
return x >= mod ? x - mod : x;
}
template <int mod>
struct Modint
{
unsigned int x;
Modint() = default;
Modint(unsigned int x) : x(x) {}
friend istream &operator>>(istream &in, Modint &a) { return in >> a.x; }
friend ostream &operator<<(ostream &out, Modint a) { return out << a.x; }
friend Modint operator+(Modint a, Modint b) { return down<mod>(a.x + b.x); }
friend Modint operator-(Modint a, Modint b) { return down<mod>(a.x - b.x + mod); }
friend Modint operator*(Modint a, Modint b) { return 1ULL * a.x * b.x % mod; }
friend Modint operator/(Modint a, Modint b) { return a * ~b; }
friend Modint operator^(Modint a, i64 b)
{
Modint ans = 1;
for (; b; b >>= 1, a *= a)
if (b & 1)
ans *= a;
return ans;
}
friend Modint operator~(Modint a) { return a ^ (mod - 2); }
friend Modint operator-(Modint a) { return down<mod>(mod - a.x); }
friend Modint &operator+=(Modint &a, Modint b) { return a = a + b; }
friend Modint &operator-=(Modint &a, Modint b) { return a = a - b; }
friend Modint &operator*=(Modint &a, Modint b) { return a = a * b; }
friend Modint &operator/=(Modint &a, Modint b) { return a = a / b; }
friend Modint &operator^=(Modint &a, i64 b) { return a = a ^ b; }
friend Modint &operator++(Modint &a) { return a += 1; }
friend Modint operator++(Modint &a, int)
{
Modint x = a;
a += 1;
return x;
}
friend Modint &operator--(Modint &a) { return a -= 1; }
friend Modint operator--(Modint &a, int)
{
Modint x = a;
a -= 1;
return x;
}
friend bool operator==(Modint a, Modint b) { return a.x == b.x; }
friend bool operator!=(Modint a, Modint b) { return !(a == b); }
};
const int mod = 998244353;
typedef Modint<mod> mint;
long double mypow(long double x, int y)
{
long double ret = 1;
while (y)
{
if (y & 1)
ret *= x;
x *= x;
y >>= 1;
}
return ret;
}
bool Memory_end;
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cerr << (&Memory_end - &Memory_begin) / 1048576.0 << "MB" << '\n';
int n, k;
cin >> n >> k;
const long double e = 1.0;
long double p;
cin >> p;
cout << fixed << setprecision(10);
clock_t cur = clock();
vector<long double> dp(n + 2), a = dp, b = a;
for (int i = n; i >= 1; i--)
{
a[i] = p, b[i] = e;
a[i] += (e - p) * a[i + 1];
b[i] += (e - p) * b[i + 1];
}
dp[1] = b[1] / (e - a[1]);
for (int i = n; i >= 2; i--)
dp[i] = e + p * dp[1] + (e - p) * dp[i + 1];
int idx = 0;
while (k-- and clock() - cur <= 1488)
{
auto tmp = dp;
for (int i = n; i >= 1; i--)
tmp[i] = e + p * dp[i] + (e - p) * tmp[i + 1];
auto cal = [&](int c) -> long double
{
if (c == n)
return tmp[1];
long double d = (e - mypow(e - p, n - c)) / p;
long double b = mypow(e - p, n - c) * tmp[n - c + 1] + d;
long double a = d * p;
return b / (e - a);
// vector<long double> ret(n + 2);
// for (int i = n; i >= n - c + 1; i--)
// {
// ret[i] = e + p * dp[i] + (e - p) * ret[i + 1];
// a[i] = 0, b[i] = ret[i];
// }
// for (int i = n - c; i >= 1; i--)
// {
// a[i] = p, b[i] = e;
// a[i] += (e - p) * a[i + 1];
// b[i] += (e - p) * b[i + 1];
// }
// ret[1] = b[1] / (e - a[1]);
// for (int i = n - c; i >= 2; i--)
// ret[i] = e + p * ret[1] + (e - p) * ret[i + 1];
// return ret;
};
while (idx < n)
{
auto dp1 = cal(idx), dp2 = cal(idx + 1);
if (dp1 > dp2)
idx++;
else
break;
}
tmp[1] = cal(idx);
for (int i = n - idx; i >= 2; i--)
tmp[i] = e + p * tmp[1] + (e - p) * tmp[i + 1];
dp = move(tmp);
}
cout << dp[1] << '\n';
}
/*
*/
詳細信息
Test #1:
score: 100
Accepted
time: 1ms
memory: 4064kb
input:
5 0 0.5
output:
62.0000000000
result:
ok found '62.000000000', expected '62.000000000', error '0.000000000'
Test #2:
score: 0
Accepted
time: 0ms
memory: 3900kb
input:
5 1 0.5
output:
47.0000000000
result:
ok found '47.000000000', expected '47.000000000', error '0.000000000'
Test #3:
score: 0
Accepted
time: 1ms
memory: 3908kb
input:
10000 0 0.002
output:
247489700306.9192301482
result:
ok found '247489700306.919219971', expected '247489700298.253692627', error '0.000000000'
Test #4:
score: -100
Wrong Answer
time: 0ms
memory: 8260kb
input:
100000 10 0.0002
output:
2430683127369.9571905136
result:
wrong answer 1st numbers differ - expected: '38767507133.2322159', found: '2430683127369.9570312', error = '61.6989793'