题解 | 二元素数组

n = int(input())
primes = []
isPrime = [False, False] + [True] * n
for i in range(2, n):
    if isPrime[i]:
        primes.append(i)
    for prime in primes:
        if i * prime >= n:
            break
        isPrime[i * prime] = False
        if i % prime == 0:
            break
for a in primes:
    if a > n - a:
        break
    if isPrime[n - a]:
        print(a, n - a)