简化：在合并索引文件过程，word相同时，没必要比较doc_id,因索引文件是按序产生

[Google1234]

                if int(doc1[i])<int(doc2[j]):
                    write_block1.push(':'+doc1[i]+'#'+tf1[i])
                    i+=1
                else:
                    if int(doc1[i])>int(doc2[j]):
                        write_block1.push(':'+doc2[j]+'#'+tf2[j])
                        j+=1
                    else:
                        write_block1.push(':'+doc2[j]+'#'+str(int(tf1[i])+int(tf2[j])))
                        i+=1
                        j+=1