In the city of Dingilville the traffic is arranged in an unusual way.
There are junctions and roads connecting the junctions. There is at most one road between
any two different junctions. There is no road connecting a junction to itself. Travel time
for a road is the same for both directions. At every junction there is a single traffic
light that is either blue or purple at any moment. The color of each light alternates
periodically: blue for certain duration and then purple for another duration. Traffic is
permitted to travel down the road between any two junctions, if and only if the lights at both
junctions are the same color at the moment of departing from one junction for the
other. If a vehicle arrives at a junction just at the moment the lights switch it must
consider the new colors of lights. Vehicles are allowed to wait at the junctions. You are
given the city map which shows
- the travel times for all roads (integers),
- the durations of the two colors at each junction (integers)
- and the initial color of the light and the remaining time (integer) for this color to
change at each junction.
Your task is to find a path which takes the minimum time from a given
source junction to a given destination junction for a vehicle when the traffic starts. In
case more than one such path exists you are required to report only one of them.
2 <= N <=300 where N is
the number of junctions. The junctions are identified by integers 1 through N.
These numbers are called id-numbers.
1 <=M <=14,000 where M
is the number of roads.
1 <= lij <= 100
where lij is the time required to move from junction i to j using
the road that connects i and j.
1 <= tic <= 100
where tic is the duration of the color c for the light at the
junction i. The index c is either B for blue or P for
1 <= ric <= tic
where ric is the remaining time for the initial color c
at junction i.
The input is a text file named lights.inp.
- The first line contains two numbers: The id-number of the source junction and the
id-number of the destination junction.
- The second line contains two numbers: N, M.
- The following N lines contain information on N junctions. The (i+2)th
line of the input file holds information about the junction i : Ci,
ric, tiB, tiP where Ci is
either B or P,
indicating the initial color of the light at the junction i.
- Finally, the next M lines contain information on M roads. Each line is of
the form: i, j, lij where i and j are the
id-numbers of the junctions which are connected by this road .
The output must be a text file named lights.out.
If a path exists:
The first line will contain the time taken by a minimum-time path from the source
junction to the destination junction.
Second line will contain the list of junctions that construct the minimum-time path you
have found. You have to write the junctions to the output file in the order of travelling.
Therefore the first integer in this line must be the id-number of the source junction and
the last one the id-number of the destination junction.
If a path does not exist:
- A single line containing only the integer 0.
Your program will be allowed to run 2 seconds.
No partial credit can be obtained for a test case.