WC '17 Contest 3 S4 - Relevant Results
View as PDFWoburn Challenge 2017-18 Round 3 - Senior Division

You own a group of  
 webpages dedicated solely
to the art of dynamic programming. Each page 
 includes links to
 
 other distinct pages, the 
-th of which is
page 
 
. The total number of links
 is at most 
. You consider a given page 
 to be
"accessible" from a given page 
 if it's possible to follow a sequence
of 0 or more links starting from page 
 and ending at page 
.
Unfortunately, your pages aren't getting as much traffic as you'd like. It's clear that the most promising way of encouraging more people to come across your pages is to somehow cause them to appear earlier in the search results when someone searches for "dynamic programming" on the internet's most popular search engine.
Each page is assigned an integral "relevancy score" for a given search
query such as "dynamic programming", and pages with higher scores then
appear earlier in the results for that query. Page 's initial
relevancy score is 
 
. Fortunately, if
you donate 
 
 dollars to the search
engine company, you can increase page 
's score by 
! You can choose
to do so 
 or more times for any page.
You're not yet sure about how much money you'd like to spend on helping
to make your pages "more relevant", so you'll consider a series of 
 independent questions. For the 
-th question,
you'd like to determine the minimum amount of money you'd need to spend
in order to make all 
 of your pages "accessible" from search results
with relevancy scores no smaller than 
 
.
In other words, after you finish increasing all of the pages'
scores as necessary, for each page 
 
, there must
exist at least one page 
 such that page 
's final relevancy score
is greater than or equal to 
 and page 
 is accessible from page
. Note that all 
 questions are independent, with changes to pages'
scores not carrying over between them.
Subtasks
In test cases worth  of the points, 
,
, and 
.
In test cases worth another  of the points, 
.
Input Specification
The first line of input consists of a single integer, .
 lines follow, the 
-th of which consists of three space-separated
integers, 
, 
, and 
, followed by 
 more
integers 
, for 
.
The next line consists of a single integer, .
 lines follow, the 
-th of which consists of a single integer,
, for 
.
Output Specification
Output  lines, the 
-th of which should consist of a single real
number, the minimum cost (in dollars) required such that all 
 pages
are accessible from search results with relevancy scores no smaller than
.
Sample Input
5
9 3 1 4
11 1 0
8 2 1 1
4 2 1 3
7 2 1 2
3
10
12
1
Sample Output
9
18
0
Sample Explanation
If page 's relevancy score is increased to 
 (for a cost of 
) and
page 
's relevancy score is also increased to 
 (for a cost of 
),
then all 
 pages will be reachable from search results with relevancy
scores no smaller than 
. Pages 
, 
, and 
 will have sufficiently high
relevancy score themselves, and page 
 links to page 
 which then links
to page 
. This total cost of 
 is optimal.
Comments