Buggy python submission (verdict: Runtime Error):
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 3)] for y in range(N + 3)]

    def recur(i, k):
        if not i < N:
            return 1

        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)


Fixed submission:
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 3)] for y in range(N + 3)]

    def recur(i, k):
        if not i < N:
            return 1

        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)

Buggy python submission (verdict: Runtime Error):
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 3)] for y in range(N + 3)]

    def recur(i, k):
        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        if not i < N:
            return 1

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)


Fixed submission:
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 3)] for y in range(N + 3)]

    def recur(i, k):
        if not i < N:
            return 1

        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)

Buggy python submission (verdict: Runtime Error):
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 1)] for y in range(N + 1)]

    def recur(i, k):
        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        if not i < N:
            return 1

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)


Fixed submission:
def solve():
    N, K = list(map(int, input().split()))

    TABLE = [[-1 for x in range(K + 3)] for y in range(N + 3)]

    def recur(i, k):
        if not i < N:
            return 1

        if not TABLE[i][k] == -1:
            return TABLE[i][k]

        ans = 0
        for a in range(K):
            if not a == k:
                ans += recur(i + 1, a)

        TABLE[i][k] = ans
        return TABLE[i][k]

    return recur(0, -1)


if __name__ == '__main__':
    res = solve()
    print(res)