codeflash-internal/experiments/pie_test_set/p02875.py

18 lines
356 B
Python

def problem_p02875(input_data):
n = int(eval(input_data))
l = [0, 1]
a = 0
b = c = 1
p = 998244353
for i in range(2, n):
l += [l[p % i] * (p - int(p / i)) % p]
for i in range(n, n // 2, -1):
a += b * c % p
b = 2 * b % p
c = c * i * l[n + 1 - i] % p
return (pow(3, n, p) - 2 * a + p) % p