codility Fish

Question:codility Lesson7 Fish

My Answer:

def solution(A,B):
    cnt = 0
    downstream = []
    downcnt = 0

    for i in range(len(A)):
        if B[i] == 1:
            downstream.append(A[i])
        else:
            while downcnt != 0:
                if downstream[-1] < A[i]:
                    downcnt -= 1
                    downstream.pop()
                else:
                    break
            else:
                cnt += 1
    cnt += len(downstream)
    return cnt