Problem p03033 (python)

Fixed submission:
import collections


def main():
    from sys import stdin, stdout

    read = iter(stdin.read().splitlines()).next
    #def read():
    #    return stdin.readline().rstrip('\n')

    def read_array(sep=None, maxsplit=-1):
        return read().split(sep, maxsplit)

    def read_int():
        return int(read())

    def read_int_array(sep=None, maxsplit=-1):
        return [int(a) for a in read_array(sep, maxsplit)]

    def write(*args, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in args) + end)

    def write_array(array, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in array) + end)

    N, Q = read_int_array()
    updates1 = []
    updates2 = []
    for i in range(N):
        S, T, X = read_int_array()
        updates1.append((S - X, X))
        updates2.append((T - X, X))

    active = []
    to_delete = collections.defaultdict(int)
    import heapq
    heapq.heapify(updates1)
    heapq.heapify(updates2)
    for _ in range(Q):
        x = read_int()
        while updates1 and updates1[0][0] <= x:
            coord, val = heapq.heappop(updates1)
            heapq.heappush(active, val)

        while updates2 and updates2[0][0] <= x:
            coord, val = heapq.heappop(updates2)
            to_delete[val] += 1

        while active and to_delete[active[0]] > 0:
            to_delete[active[0]] -= 1
            heapq.heappop(active)
        write(active[0] if active else -1)

main()

Buggy submission (verdict: Runtime Error):
import collections


def main():
    from sys import stdin, stdout

    read = iter(stdin.read().splitlines()).next
    #def read():
    #    return stdin.readline().rstrip('\n')

    def read_array(sep=None, maxsplit=-1):
        return read().split(sep, maxsplit)

    def read_int():
        return int(read())

    def read_int_array(sep=None, maxsplit=-1):
        return [int(a) for a in read_array(sep, maxsplit)]

    def write(*args, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in args) + end)

    def write_array(array, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in array) + end)

    N, Q = [int(x) for x in input().split()]
    updates1 = []
    updates2 = []
    for i in range(N):
        S, T, X = [int(x) for x in input().split()]
        updates1.append((S - X, X))
        updates2.append((T - X, X))

    active = []
    to_delete = collections.defaultdict(int)
    import heapq
    heapq.heapify(updates1)
    heapq.heapify(updates2)
    for _ in range(Q):
        x = int(input())
        while updates1 and updates1[0][0] <= x:
            coord, val = heapq.heappop(updates1)
            heapq.heappush(active, val)

        while updates2 and updates2[0][0] <= x:
            coord, val = heapq.heappop(updates2)
            to_delete[val] += 1

        while active and to_delete[active[0]] > 0:
            to_delete[active[0]] -= 1
            heapq.heappop(active)
        write(active[0] if active else -1)

main()

Buggy submission (verdict: Runtime Error):
import collections


def main():
    from sys import stdin, stdout

    read = iter(sys.stdin.read().splitlines()).next
    #def read():
    #    return stdin.readline().rstrip('\n')

    def read_array(sep=None, maxsplit=-1):
        return read().split(sep, maxsplit)

    def read_int():
        return int(read())

    def read_int_array(sep=None, maxsplit=-1):
        return [int(a) for a in read_array(sep, maxsplit)]

    def write(*args, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in args) + end)

    def write_array(array, **kwargs):
        sep = kwargs.get('sep', ' ')
        end = kwargs.get('end', '\n')
        stdout.write(sep.join(str(a) for a in array) + end)

    N, Q = [int(x) for x in input().split()]
    updates1 = []
    updates2 = []
    for i in range(N):
        S, T, X = [int(x) for x in input().split()]
        updates1.append((S - X, X))
        updates2.append((T - X, X))

    active = []
    to_delete = collections.defaultdict(int)
    import heapq
    heapq.heapify(updates1)
    heapq.heapify(updates2)
    for _ in range(Q):
        x = int(input())
        while updates1 and updates1[0][0] <= x:
            coord, val = heapq.heappop(updates1)
            heapq.heappush(active, val)

        while updates2 and updates2[0][0] <= x:
            coord, val = heapq.heappop(updates2)
            to_delete[val] += 1

        while active and to_delete[active[0]] > 0:
            to_delete[active[0]] -= 1
            heapq.heappop(active)
        write(active[0] if active else -1)

main()