結果

問題 No.2068 Restricted Permutation
ユーザー 👑 rin204
提出日時 2022-09-02 22:02:18
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 148 ms / 2,000 ms
コード長 2,381 bytes
コンパイル時間 314 ms
コンパイル使用メモリ 82,396 KB
実行使用メモリ 126,848 KB
最終ジャッジ日時 2024-11-16 03:29:56
合計ジャッジ時間 4,390 ms
ジャッジサーバーID
(参考情報)
judge5 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 23
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

# https://atcoder.jp/contests/code-festival-2016-qualc/submissions/33924036
from bisect import bisect
class Bit:
def __init__(self, n):
self.size = n
self.n0 = 1 << (n.bit_length() - 1)
self.tree = [0] * (n + 1)
def range_sum(self, l, r):
return self.sum(r - 1) - self.sum(l - 1)
def sum(self, i):
i += 1
s = 0
while i > 0:
s += self.tree[i]
i -= i & -i
return s
def get(self, i):
return self.sum(i) - self.sum(i - 1)
def add(self, i, x):
i += 1
while i <= self.size:
self.tree[i] += x
i += i & -i
def lower_bound(self, x):
pos = 0
plus = self.n0
while plus > 0:
if pos + plus <= self.size and self.tree[pos + plus] < x:
x -= self.tree[pos + plus]
pos += plus
plus //= 2
return pos
MOD = 998244353
N = 2000000
fact = [0 for _ in range(N)]
invfact = [0 for _ in range(N)]
fact[0] = 1
for i in range(1, N):
fact[i] = fact[i - 1] * i % MOD
invfact[N - 1] = pow(fact[N - 1], MOD - 2, MOD)
for i in range(N - 2, -1, -1):
invfact[i] = invfact[i + 1] * (i + 1) % MOD
def nCk(n, k):
if k < 0 or n < k:
return 0
else:
return (fact[n] * invfact[k] % MOD) * invfact[n - k] % MOD
def nPk(n, k):
if k < 0 or n < k:
return 0
else:
return fact[n] * invfact[n - k] % MOD
def nHk(n, k):
if n == k == 0:
return 1
return nCk(n + k - 1, k)
n, k, x = map(int, input().split())
P = [0] * n
P[k - 1] = x
P = P[::-1]
tf = [False] * (n + 1)
ind = []
for i, p in enumerate(P):
tf[p] = True
lst = []
for i in range(1, n + 1):
if not tf[i]:
lst.append(i)
inv2 = pow(2, MOD - 2, MOD)
ans = 0
l = len(lst)
invl = pow(l, MOD - 2, MOD)
bit = Bit(n + 1)
x = 0
t = 0
for i, p in enumerate(P):
if p == 0:
ans += (x * fact[i]) * inv2 % MOD
ans %= MOD
x += 1
ans += (t * fact[i] % MOD) * invl % MOD
ans %= MOD
else:
c = bit.sum(p)
ans += fact[i] * c % MOD
ans %= MOD
bit.add(p, 1)
c = bisect(lst, p)
ans += (c * invl % MOD) * (fact[i] * x % MOD) % MOD
ans %= MOD
t += l - c
ans *= fact[l]
ans %= MOD
print(ans)
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