2202. Cheap travels

单点时限: 2.0 sec

内存限制: 256 MB

A coach trip by a transcontinental motorway lasts many days so payments for hotels are a serious part of the travel cost.

For the sake of safety and comfort coaches travel only in the daytime and can make at most 800 km a day. During the trip the

driver and passengers spend nights in hotels (it does not concern the beginning and the end of the trip). So far travels were

planned to minimize the number of nights spent in hotels. To decrease the cost the firm organizing travels decided to find out

if it is commercially viable to plan the travels in such a way that the sum of payments for hotels is minimal (even if it extends

the time of travel). Offers of hotels situated along the motorway should be used in calculations. Each offer consists of the

distance between the hotel and the beginning of the route and the price of a single night for one person in the hotel. The travel

is one-way. The route does not fork. At each point of the route the coach is only once. To identify a hotel it is enough to give its

distance from the beginning of the route, i.e. at each point of the route there is at most one hotel. Nights at the beginning and at

the end of the route are not planned. The number of passengers is constant and in every hotel all of them and the driver pay for

the night the same amount - according to the offer. We assume that the capacities of hotels are big enough to place all the passengers.

There is at least one hotel in every fragment of the route of length 800 km, so travel can be always made according to the given conditions.

Write a program that:

    * reads the following data: the length of the route, the number of hotels and the offers of hotels;

* finds two plans of travel:

@ a plan of the cheapest travel (the sum of payments for hotels is minimal); if there is more than one solution the program

should chose the one with the minimal number of nights in hotels,

@ a plan of the shortest travel (the number of nights in hotels is minimal); if there is more than one solutions the program

should chose the one with the minimal sum of payments for hotels;

* writes the results, i.e. two plans of travel - the cheapest and the shortest.

输入格式

In the first line there are written two positive integers separated by a single space. The first integer d is the length of the

route given in kilometres. The second integer h is the number of hotels, d <= 16000, h <= 1000. In the following h lines there

are written the offers of hotels - one offer in one line. The offers are ordered according to the increasing distance of hotels from

the beginning of the route. Each offer consists of two positive integers separated by a single space. The first integer is the

distance of the hotel from the beginning of the route and is given in kilometres. The second integer is the price of a single night

in this hotel and is not greater than 1000.

输出格式

In the first line there should be written the plan of the cheapest travel, i.e. the distances from the beginning of the route of

the hotels in which we decide to spend nights. In the second line there should be written, in a similar way, the plan of the

shortest travel. The numbers in each line should be separated by a single space.

样例

Input
2000 7
100 54
120 70
400 17
700 38
1000 25
1200 18
1440 40
Output
400 1200
400 1200

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创建: 16 年,4 月前.

修改: 7 年,2 月前.

最后提交: 16 年,4 月前.

来源: POI 1997 I Stage

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