一共4部电话编号为1，2，3，4，电话分别在不同的房间内，3个接线员，编号为A，B，C。A只负责1，2号电话，B负责2，3号电话，C负责3，4号电话。假设单位时间为1，在每一个单位时间内，每个接线员可以回复一个房间内的电话，或者从一个房间走的另一个房间。但是每个房间同一时间只能有一个人。给出时间段x内的所有电话的情况，编程输出最多能答复的电话数。（A，B，C的最初位置可以按情况自己选择）-A total of four phone numbers for the 1,2,3,4, phones in different rooms, three operators, numbered A, B, C. A telephone number is only responsible for 1,2, B 2,3 Tel responsible for, C for 3,4 Tel. Assuming the time is 1, in each unit time, each operator can return the phone within a room, or walking from one room to another room. Each room at the same time, however only one person. X within the given time period the situation of all phone, programming the output up to answer the telephone number. (A, B, C' s initial position can choose the circumstances)