CTF--Project_Euler--50-Consecutive_prime_sum.txt

### 50-Consecutive prime sum
"""Which prime, below one-million, can be written as the sum of the most consecutive primes?"""
limit = 1000000

def is_prime(n: int) -> bool:
    if n <= 3:
        return n > 1
    if n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    while i ** 2 <= n:
        if n % i == 0 or n % (i + 2) == 0:
            return False
        i += 6
    return True

primes = [x for x in range(2, limit) if is_prime(x)]

nsum = count = 0
sums1 = []
results = []

for i in primes:
    if nsum + i >= limit:
        break
    nsum += i
    count += 1
    sums1.append(i)

sums2 = sums1.copy()
count2 = count

tnum = tcount = 0
while len(sums1) > 0:
    nsum = sum(sums1)
    while not is_prime(nsum):
        sums1.pop()
        count -= 1
        nsum = sum(sums1)
    if count >= tcount:
        tcount = count
        tnum = nsum
    sums1.pop(0)
    count -= 1
results.append([tnum, tcount])

tnum = tcount = 0
while len(sums2) > 0:
    nsum = sum(sums2)
    while not is_prime(nsum):
        sums2.pop(0)
        count2 -= 1
        nsum = sum(sums2)
    if count2 >= tcount:
        tcount = count2
        tnum = nsum
    sums2.pop()
    count2 -= 1
results.append([tnum, tcount])

maxcount = maxnum = 0
for i in results:
    if i[1] > maxcount:
        maxcount = i[1]
        maxnum = i[0]

print(maxnum)