結果

問題 No.2406 Difference of Coordinate Squared
ユーザー chineristAC
提出日時 2023-08-04 22:45:51
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 163 ms / 2,000 ms
コード長 2,093 bytes
コンパイル時間 363 ms
コンパイル使用メモリ 82,176 KB
実行使用メモリ 99,712 KB
最終ジャッジ日時 2024-11-26 18:05:08
合計ジャッジ時間 8,067 ms
ジャッジサーバーID
(参考情報)
judge1 / judge2
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 * 2
other AC * 55
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ソースコード

diff #
プレゼンテーションモードにする

import sys
input = lambda :sys.stdin.readline().rstrip()
def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
return (g1[n] * g2[r] % mod) * g2[n-r] % mod
mod = 998244353
N = 10**6 + 10
g1 = [1]*(N+1)
g2 = [1]*(N+1)
inverse = [1]*(N+1)
for i in range( 2, N + 1 ):
g1[i]=( ( g1[i-1] * i ) % mod )
inverse[i]=( ( -inverse[mod % i] * (mod//i) ) % mod )
g2[i]=( (g2[i-1] * inverse[i]) % mod )
inverse[0]=0
N,M = map(int,input().split())
if M == 0:
res = 0
"""
X+Y = 0
"""
if N & 1 == 0:
res += cmb(N,N//2,mod) * pow(inverse[2],N,mod) * 2 % mod
res %= mod
res -= cmb(N,N//2,mod) * cmb(N,N//2,mod) * pow(inverse[2],2*N,mod) % mod
res %= mod
print(res)
else:
divisors = []
for d in range(1,abs(M)+1):
if d*d > abs(M):
break
if M % d == 0:
divisors.append(d)
divisors.append(-d)
if abs(M)//d != d:
divisors.append(M//d)
divisors.append(-M//d)
divisors.sort()
res = 0
for d in divisors:
p = d
m = M // d
tmp = 1
if (N+p) & 1 == 0 and 0 <= (N+p)//2 <= N:
tmp *= cmb(N,(N+p)//2,mod)
tmp %= mod
else:
tmp = 0
if (N+m) & 1 == 0 and 0 <= (N+m)//2 <= N:
tmp *= cmb(N,(N+m)//2,mod)
tmp %= mod
else:
tmp = 0
res += tmp
res %= mod
res *= pow(inverse[4],N,mod)
res %= mod
print(res)
exit()
dp = [[0]*(2*N+1) for i in range(2*N+1)]
dp[0][0] = 1
for _ in range(N):
ndp = [[0]*(2*N+1) for i in range(2*N+1)]
for i in range(-N,N+1):
for j in range(-N,N+1):
if not dp[i][j]:
continue
for ni,nj in [(i-1,j),(i+1,j),(i,j-1),(i,j+1)]:
ndp[ni][nj] += dp[i][j] * inverse[4] % mod
ndp[ni][nj] %= mod
dp = ndp
check = 0
for i in range(-N,N+1):
for j in range(-N,N+1):
if i*i-j*j == M:
check += dp[i][j]
check %= mod
print(check)
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