Problem p02616 (python)

Fixed submission:
def main():
    N, K = map(int, input().split())
    A = list(map(int, input().split()))
    mod = 7 + 10**9
    if N == K:
        r = 1
        for i in A:
            r *= i
            r %= mod
        return r % mod
    if max(A) <= 0 and K % 2 == 1:
        A.sort(reverse=True)
        r = 1
        for i in range(K):
            r *= A[i]
            r %= mod
        return r % mod
    a = []
    for i in A:
        a.append((abs(i), i))
    a.sort(reverse=True)
    cm = 0
    lp = None
    lm = None
    for i in range(K):
        if a[i][1] >= 0:
            lp = i
        else:
            lm = i
            cm += 1
    if cm % 2 == 0:
        r = 1
        for i in range(K):
            r *= a[i][1]
            r %= mod
        return r
    if not lp:
        r = 1
        for i in range(K-1):
            r *= a[i][1]
            r %= mod
        r *= max(A)
        return r % mod
    np = None
    nm = None
    for i in range(K, N):
        if a[i][1] >= 0 and not np:
            np = i
        if a[i][1] < 0 and not nm:
            nm = i
        if np and nm:
            break
    if not np:
        r = 1
        for i in range(K):
            if i != lp:
                r *= a[i][1]
                r %= mod
        r *= a[nm][1]
        return r % mod
    if not nm:
        r = 1
        for i in range(K):
            if i != lm:
                r *= a[i][1]
                r %= mod
        r *= a[np][1]
        return r % mod
    r = 1
    for i in range(K):
        if i not in (lp, lm):
            r *= a[i][1]
            r %= mod
    r *= max(a[np][1] * a[lp][1], a[lm][1] * a[nm][1])
    return r % mod
print(main())

Buggy submission (verdict: Runtime Error):
def main():
    N, K = map(int, input().split())
    A = list(map(int, input().split()))
    mod = 7 + 10**9
    if N == K:
        r = 1
        for i in A:
            r *= i
            r %= mod
        return r % mod
    if max(A) == 0 and K % 2 == 1:
        return 0
    if max(A) < 0 and K % 2 == 1:
        A.sort(reverse=True)
        r = 1
        for i in range(K):
            r *= A[i]
            r %= mod
        return r % mod
    a = []
    for i in A:
        a.append((abs(i), i))
    a.sort(reverse=True)
    cm = 0
    lp = None
    lm = None
    for i in range(K):
        if a[i][1] >= 0:
            lp = i
        else:
            lm = i
            cm += 1
    if cm % 2 == 0:
        r = 1
        for i in range(K):
            r *= a[i][1]
            r %= mod
        return r
    if not lp:
        r = 1
        for i in range(K-1):
            r *= a[i][1]
            r %= mod
        for i in range(K+1, N):
            if a[i][1] > 0:
                r *= a[i][1]
                r %= mod
                return r
    np = None
    nm = None
    for i in range(K+1, N):
        if a[i][1] >= 0 and not np:
            np = i
        if a[i][1] < 0 and not nm:
            nm = i
        if np and nm:
            break
    if not np:
        r = 1
        for i in range(K):
            if i != lp:
                r *= a[i][1]
                r %= mod
        r *= a[nm][1]
        return r % mod
    if not nm:
        r = 1
        for i in range(K):
            if i != lm:
                r *= a[i][1]
                r %= mod
        r *= a[np][1]
        return r % mod
    r = 1
    for i in range(K):
        if i not in (lp, lm):
            r *= a[i][1]
    r *= max(a[np][1] * a[lp][1], a[lm][1] * a[nm][1])
    return r % mod
print(main())