Buggy python submission (verdict: Time Limit Exceeded):
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
from sys import stdin

while True:
    n = int(stdin.readline())
    if not n:
        break
    m = 0
    tup = tuple(int(stdin.readline()) for _ in xrange(n))
    for i in xrange(len(tup)):
        for j in xrange(1 + i, len(tup) + 1):
            t = sum(tup[i:j])
            if t > m:
                m = t
    print(m)

Fixed submission:
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin
from array import array

def grouping(nums):
    sign = None
    L = array(b'i')
    for s, n in ((i < 0, i) for i in nums):
        if sign is s:
            L[-1] += n
        else:
            sign = s
            L.append(n)

    if len(L) and L[-1] <= 0:
        del L[-1]
    if len(L) and L[0] <= 0:
        del L[0]
    return L

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = array(b'i', (int(stdin.readline()) for _ in xrange(n)))
    val = max(L)
    if val <= 0:
        print(val)
        continue

    ans, temp = 0, 0
    for i in grouping(L):
        temp = max(0, temp+i)
        ans = max(ans, temp)
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
from sys import stdin

while True:
    n = int(stdin.readline())
    if not n:
        break

    tup = tuple(int(stdin.readline()) for _ in xrange(n))
    L = [tup[0]]
    for i in tup[1:]:
        if 0 > i and 0 > L[-1]:
            L[-1] += i
        elif 0 <= i and 0 <= L[-1]:
            L[-1] += i
        else:
            L.append(i)

    m = 0
    for i in xrange(len(L)):
        for j in xrange(1 + i, len(L) + 1):
            t = sum(L[i:j])
            if t > m:
                m = t
    print(m)

Fixed submission:
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin
from array import array

def grouping(nums):
    sign = None
    L = array(b'i')
    for s, n in ((i < 0, i) for i in nums):
        if sign is s:
            L[-1] += n
        else:
            sign = s
            L.append(n)

    if len(L) and L[-1] <= 0:
        del L[-1]
    if len(L) and L[0] <= 0:
        del L[0]
    return L

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = array(b'i', (int(stdin.readline()) for _ in xrange(n)))
    val = max(L)
    if val <= 0:
        print(val)
        continue

    ans, temp = 0, 0
    for i in grouping(L):
        temp = max(0, temp+i)
        ans = max(ans, temp)
    print(ans)

Buggy python submission (verdict: Runtime Error):
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
from sys import stdin

while True:
    n = int(stdin.readline())
    if not n:
        break

    tup = tuple(int(stdin.readline()) for _ in xrange(n))
    L = [tup[0]]
    for i in tup[1:]:
        if 0 > i and 0 > L[-1]:
            L[-1] += i
        elif 0 <= i and 0 <= L[-1]:
            L[-1] += i
        else:
            L.append(i)

    while True:
        length = len(L)
        if L[0] <= 0:
            L.pop(0)
            continue
        if L[-1] <= 0:
            L.pop()
            continue
        if length > 1 and L[0] + L[1] <= 0:
            L.pop(0)
            L.pop(0)
            continue
        if length > 1 and L[-1] + L[-2] <= 0:
            L.pop()
            L.pop()
            continue
        if length > 2 and sum(L[:3]) >= L[2]:
            L[2] = sum(L[:3])
            L.pop(0)
            L.pop(0)
            continue
        if length > 2 and sum(L[-3:]) >= L[-3]:
            L[-3] = sum(L[-3:])
            L.pop(0)
            L.pop(0)
            continue
        break

    m = 0
    for i in xrange(len(L)):
        for j in xrange(1 + i, len(L) + 1):
            t = sum(L[i:j])
            if t > m:
                m = t
    print(m)

Fixed submission:
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin
from array import array

def grouping(nums):
    sign = None
    L = array(b'i')
    for s, n in ((i < 0, i) for i in nums):
        if sign is s:
            L[-1] += n
        else:
            sign = s
            L.append(n)

    if len(L) and L[-1] <= 0:
        del L[-1]
    if len(L) and L[0] <= 0:
        del L[0]
    return L

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = array(b'i', (int(stdin.readline()) for _ in xrange(n)))
    val = max(L)
    if val <= 0:
        print(val)
        continue

    ans, temp = 0, 0
    for i in grouping(L):
        temp = max(0, temp+i)
        ans = max(ans, temp)
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
from sys import stdin

while True:
    n = int(stdin.readline())
    if not n:
        break

    tup = tuple(int(stdin.readline()) for _ in xrange(n))
    L = [tup[0]]
    for i in tup[1:]:
        if 0 > i and 0 > L[-1]:
            L[-1] += i
        elif 0 <= i and 0 <= L[-1]:
            L[-1] += i
        else:
            L.append(i)

    while True:
        length = len(L)
        if length > 1 and L[0] <= 0:
            L.pop(0)
            continue
        if length > 1 and L[-1] <= 0:
            L.pop()
            continue
        if length > 1 and L[0] + L[1] <= 0:
            L.pop(0)
            L.pop(0)
            continue
        if length > 1 and L[-1] + L[-2] <= 0:
            L.pop()
            L.pop()
            continue
        break
    print(L)

    m = 0
    for i in xrange(len(L)):
        for j in xrange(1 + i, len(L) + 1):
            t = sum(L[i:j])
            if t > m:
                m = t
    print(m)

Fixed submission:
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin
from array import array

def grouping(nums):
    sign = None
    L = array(b'i')
    for s, n in ((i < 0, i) for i in nums):
        if sign is s:
            L[-1] += n
        else:
            sign = s
            L.append(n)

    if len(L) and L[-1] <= 0:
        del L[-1]
    if len(L) and L[0] <= 0:
        del L[0]
    return L

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = array(b'i', (int(stdin.readline()) for _ in xrange(n)))
    val = max(L)
    if val <= 0:
        print(val)
        continue

    ans, temp = 0, 0
    for i in grouping(L):
        temp = max(0, temp+i)
        ans = max(ans, temp)
    print(ans)

Buggy python submission (verdict: Runtime Error):
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin

def grouping(nums):
    it = iter(nums)
    L = [next(nums)]
    minus = L[0] < 0
    for n in it:
        if (n < 0 and minus) or (n >= 0 and not minus):
            L[-1] += n
        else:
            L.append(n)
            minus = not minus
    return L

def collect(nl):
    result = 0
    while len(nl) > 1:
        nl = grouping(nl[i] + nl[i+1] for i in xrange(0, len(nl), 2))
        if nl[-1] <= 0:
            nl.pop()
            if not len(nl):
                break
        if nl[0] >= 0:
            result += nl[0]
            nl.pop(0)
    return result

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = grouping(int(stdin.readline()) for _ in xrange(n))
    if L[0] <= 0:
        L.pop(0)
    if L[-1] <= 0:
        L.pop()

    val = max(L)
    idx = L.index(val)

    val += collect(list(reversed(L[:idx])))
    val += collect(L[idx+1:])
    print(val)

Fixed submission:
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin
from array import array

def grouping(nums):
    sign = None
    L = array(b'i')
    for s, n in ((i < 0, i) for i in nums):
        if sign is s:
            L[-1] += n
        else:
            sign = s
            L.append(n)

    if len(L) and L[-1] <= 0:
        del L[-1]
    if len(L) and L[0] <= 0:
        del L[0]
    return L

while True:
    n = int(stdin.readline())
    if not n:
        break

    L = array(b'i', (int(stdin.readline()) for _ in xrange(n)))
    val = max(L)
    if val <= 0:
        print(val)
        continue

    ans, temp = 0, 0
    for i in grouping(L):
        temp = max(0, temp+i)
        ans = max(ans, temp)
    print(ans)