Inverted Index Map Reduce

主要是要实现对于reducer机器下的值有序化，唯一化

'''
Definition of Document
class Document:
    def __init__(self, id, cotent):
        self.id = id
        self.content = content
'''
class InvertedIndex:

    # @param {Document} value is a document
    def mapper(self, _, value):
        # Write your code here
        # Please use 'yield key, value' here
        for string in value.content.split():
            yield string, value.id


    # @param key is from mapper
    # @param values is a set of value with the same key
    def reducer(self, key, values):
        # Write your code here
        # Please use 'yield key, value' here
        yield key, sorted(list(set(values)))