如何校验sequence中receiveList元素是否全部早于shipList元素出现

校验规则 #

sequence中所有属于receiveList的元素，必须全部出现在任意一个shipList元素之前。若存在任一receiveList元素出现在shipList元素之后，则判定不符合规则。

输入示例 #

receiveList = [1,2,3]
shipList = [4,5,6]
sequence = [3,1,6,2,4,5]

校验结果 #

raise('不可行的解决方案')

原因：sequence中的元素2属于receiveList，但它出现在shipList元素6之后，违反了校验规则。

Python实现代码 #

def validate_sequence(receive_list, ship_list, sequence):
    ship_element_seen = False
    for item in sequence:
        if item in ship_list:
            ship_element_seen = True
        # 若已出现过船运元素，又遇到收货元素则抛出异常
        if ship_element_seen and item in receive_list:
            raise ValueError('不可行的解决方案')
    return True

# 测试示例代码
receiveList = [1,2,3]
shipList = [4,5,6]
sequence = [3,1,6,2,4,5]
validate_sequence(receiveList, shipList, sequence)

内容的提问来源于stack exchange，提问作者Jess