Problem p02679 (python)

Fixed submission:
import math
MOD = 1000000007

def solve(N, ABs):
    groups = {}
    zero_count = 0
    for a, b in ABs:
        if a == 0 and b == 0:
            zero_count += 1
            continue
        if a == 0:
            k = (0, 1)
        elif b == 0:
            k = (1, 0)
        else:
            g = math.gcd(abs(a), abs(b))
            a //= g
            b //= g
            if a * b < 0:
                k = (abs(a), -abs(b))
            else:
                k = (abs(a), abs(b))
        groups.setdefault(k, 0)
        groups[k] += 1

    visited = set()
    possibles = []
    for k, v in groups.items():
        if k in visited:
            continue
        p = 0
        p += pow(2, v, MOD)
        if k[1] == 0:
            m = (0, 1)
        elif k[0] == 0:
            m = (1, 0)
        else:
            if k[1] < 0:
                m = (-k[1], k[0])
            else:
                m = (k[1], -k[0])


        if m in groups.keys() and m not in visited:
            p += pow(2, groups[m], MOD)
            visited.add(m)
            p -= 1
        visited.add(k)
        possibles.append(p % MOD)

    ans = 1
    for p in possibles:
        ans *= p
        ans %= MOD

    if zero_count:
        ans += zero_count
        ans %= MOD
    return (ans - 1) % MOD


def slow_solve(N, ABs):
    import itertools
    ans = 0
    for k in range(1, 2**N):
        b = ("{:0" + str(N) + "b}").format(k)
        taken = []
        for i, c in enumerate(b):
            if c == "1":
                taken.append(ABs[i])

        if len(taken) == 1:
            ans += 1
        elif all(comb[0][0] * comb[1][0] + comb[0][1] * comb[1][1] != 0
                 for comb in itertools.combinations(taken, 2)):
            ans += 1
    return ans % MOD



if __name__ == "__main__":
    N = int(input())
    ABs = [tuple(map(int, input().split(" "))) for _ in range(N)]
    print(solve(N, ABs))

Buggy submission (verdict: Runtime Error):
from decimal import *
getcontext().prec = 30
MOD = 1000000007

def solve(N, ABs):
    groups = {}
    zero_count = 0
    for a, b in ABs:
        if a == 0 and b == 0:
            zero_count += 1
            continue
        if b == 0:
            k = "INF"
        else:
            k = Decimal(a) / Decimal(b)
            k = k.quantize(Decimal("0.00000000000000000000001"))
        groups.setdefault(k, 0)
        groups[k] += 1

    visited = set()
    possibles = []
    for k, v in groups.items():
        if k in visited:
            continue
        p = 0
        p += pow(2, v, MOD)
        if k == "INF":
            m = 0
        elif k == 0:
            m = "INF"
        else:
            m = -(Decimal(1) / Decimal(k))
            m = m.quantize(Decimal("0.00000000000000000000001"))
            # print(m)
        if m in groups.keys() and m not in visited:
            p += pow(2, groups[m], MOD)
            visited.add(m)
            p -= 1
        visited.add(k)
        possibles.append(p % MOD)

    ans = 1
    for p in possibles:
        ans *= p
        ans %= MOD

    if zero_count:
        ans += zero_count
        ans %= MOD
    return (ans - 1) % MOD


def slow_solve(N, ABs):
    import itertools
    ans = 0
    for k in range(1, 2**N):
        b = ("{:0" + str(N) + "b}").format(k)
        taken = []
        for i, c in enumerate(b):
            if c == "1":
                taken.append(ABs[i])

        if len(taken) == 1:
            ans += 1
        elif all(comb[0][0] * comb[1][0] + comb[0][1] * comb[1][1] != 0
                 for comb in itertools.combinations(taken, 2)):
            ans += 1
    return ans % MOD

# print(slow_solve(3,
#       [(1, 2), (-1, 1), (2, -1)]))
#
# print(slow_solve(10,
#       [(3, 2), (3, 2), (-1, 1), (2, -1), (-3, -9), (-8, 12), (7, 7), (8, 1), (8, 2), (8, 4)]))
#
# print(slow_solve(3, [(7, 9), (-9, 7), (-4, -2)]))
# print(solve(3, [(7, 9), (-9, 7), (-4, -2)]))

# print(slow_solve(2,
# [(96, 84), (7, -8)]))
# print(solve(2,
# [(96, 84), (7, -8)]))
# input()



if __name__ == "__main__":
    N = int(input())
    ABs = [tuple(map(int, input().split(" "))) for _ in range(N)]
    print(solve(N, ABs))

Buggy submission (verdict: Runtime Error):
MOD = 1000000007

def solve(N, ABs):
    groups = {}
    for a, b in ABs:
        k = a / b
        groups.setdefault(k, 0)
        groups[k] += 1

    visited = set()
    possibles = []
    for k, v in groups.items():
        if k in visited:
            continue
        p = 0
        p += pow(2, v, MOD)
        m = - (1.0 / k)
        if m in groups.keys():
            p += pow(2, groups[m], MOD)
            visited.add(m)
            p -= 1
        possibles.append(p % MOD)

    ans = 1
    for p in possibles:
        ans *= p
        ans %= MOD
    return ans - 1


if __name__ == "__main__":
    N = int(input())
    ABs = [tuple(map(int, input().split(" "))) for _ in range(N)]
    print(solve(N, ABs))