Antennas
Time Limit: 10 Seconds Memory Limit: 131072 KB
In the 1D-Land which looks like a line,
everything is either 1-dimensional or 0-dimensional. Houses and
people are just two examples of 1-dimensional
or 0-dimensional objects, respectively. Indeed, each house is an interval
[a, b] and not surprisingly each person is a point. Due to the running of Maskan Mehr in the 1D-land, every person now owns a house. As a new project,
the kind government of the 1D-land
plans to provide
mobile service so that people
can simply do all their jobs remotely from their
houses. Due to the increased reputation of the two giant Mobile Telecommunication Companies MTC1 and MTC2, the 1D-land government has decided to donate the new project
to MTC1 and MTC2.
As an old strategy, MTC1 and MTC2 first sell their SIM-cards and then start installing their antennas. Based on the services advertised by each company, every
person in the 1D-Land has already bought a SIM-card
from one of companies.
Now each company knows
its subscribers and wants to locate its antennas in the 1D-land
such that every subscriber’s house is
covered by at least one antenna.
If a mobile antenna
with a covering range of R is located at a point x, it covers the interval
[x − R, x + R]. We say that an antenna covers a house, if the antenna
supports the house owner’s SIM type and there is at least one point in the house
being in the coverage interval
of the antenna.
Installing an antenna costs
C1 Toomans and C2 Toomans for MTC1 and MTC2, respectively. Since installing antennas is very costly, the two companies have signed an agreement to install shared antennas in some positions
provided that they reduce the total cost. Installing a shared antenna
costs C3 Toomans (max(C1 , C2 )
< C3 < C1 + C2 ) and this kind of antenna
can support both types of SIM-cards. No matter what the type of antennas is, all antennas have a fixed integer coverage range of R.
Given the information
of houses and their owners in the 1D-Land and the specification of antennas, your job is to help both
companies to position
their antennas such that each house
is covered by at least one antenna and the total cost gets
minimized.
Input
There are multiple test cases in the input. The first line of each test case contains 5 positive integers n ⩽ 5000 (the number of houses), R ⩽ 109 (the range of antennas), C1 (the installing cost of an antenna for MTC1), C2 (the installing cost of an antenna for MTC2) and C3 (the installing cost of a shared antenna). All costs are less than or equal to 109 . The next n lines describe houses; one house per line. A house description is composed of two positive integers a and b (0 < a ⩽ b < 109 ), specifying the house interval [a, b], and an integer with value either 1 and 2 indicating the owner’s SIM type where 1 and 2 denote MTC1 and MTC2, respectively. The input terminates with a line containing 0 0 0 0 0 which should not be processed.
Output
For
each test case, output a line containing the minimum total cost of installing antennas.
Sample Input
4 10 1000 2000 2400 10 20 1 15 30 2 60 65 1 90 100 2 0 0 0 0 0
Sample Output
5400Submit
Source: Tehran, Asia Region - Regional 2014