Head office building

Problem code: BUILDING

All submissions for this problem are available.

CodeChef Inc. owns a rectangular piece of land sized w×h. Its edges are parallel to the axes, with the bottom-left corner at (0,0) and top-right corner at (w,h). They intend to build a new head office within this land. The new office will be a square whose center is located at a point with integer coordinates, and whose diagonals are parallel to the axes and have length 2*d.

Unfortunately, there are n barricades on the land, some of which may need to be removed in order for the office to be built. The (i)th barricade is located at (Xi, Yi) and will cost Ci to remove. The office may only be built once all points it covers (including the boundaries) are free of barricades.

Request

Help them find the minimum total cost of barricade removal.

Input

 

  • The first line contains the integers w,h,d,n, respectively.
  • Within following n lines, the i-th line contains the integers Xi,Yi,Ci respectively.

 

 

Output

Output on a single line an integer which is the minimum cost found.

Example

Input:

4 3 1 4
1 3 5
3 3 4
2 2 1
2 1 2

Output:

2

Limitations

 

  • 2 <= w,h <= 1 000
  • 0 <= n <= 200 000
  • 2 <=2d <= min(w,h)
  • 0 < Ci <= 10 000
  • All the listed barricades are inside or on the boundaries of the CodeChef s land.
  • There is at most one barricade at each point.

    •  

Author: anhdq
Date Added: 5-05-2010
Time Limit: 1 sec
Source Limit: 50000 Bytes
Languages: ADA, ASM, BASH, BF, C, C99 strict, CAML, CLOJ, CLPS, CPP 4.0.0-8, CPP 4.3.2, CS2, D, ERL, F#, FORT, GO, HASK, ICK, ICON, JAR, JAVA, JS, LISP clisp, LISP sbcl, LUA, NEM, NICE, PAS fpc, PAS gpc, PERL, PERL6, PHP, PIKE, PRLG, PYTH, PYTH 3.1.2, RUBY, SCALA, SCM guile, SCM qobi, ST, TEXT, WSPC


Comments

Hi Admin, Seems that the

manurampandit @ 24 Jul 2010 09:54 PM

Hi Admin,

Seems that the answer to sample problem is 1.

if a square is drawn taking its center at (3,1), then the problem needs only "2 2 1" barricade to be removed.

Please see and verify if i am wrong.

 

Regards,

Manu

@Manu Ram Pandit: it costs 2

anhdq_adm @ 24 Jul 2010 10:00 PM

@Manu Ram Pandit: it costs 2 to remove the baricade at (2, 1) if you put the square center at (3, 1), please check the statement again ;)

just one test case?

jayeshdhamechai @ 24 Jul 2010 10:15 PM

just one test case?

@jayesh dhamechai: it may

anhdq_adm @ 24 Jul 2010 10:21 PM

@jayesh dhamechai: it may have several test cases (each follows above i/o format), and you will get accepted (and receive one point) when you can solve ALL of them :-)

so we need to process input

jayeshdhamechai @ 24 Jul 2010 10:25 PM

so we need to process input till EOF?

@jayesh dhamechai: oh no,

anhdq_adm @ 24 Jul 2010 10:29 PM

@jayesh dhamechai: oh no, each test case is like a separated file following the above i/o format which you must process, please see FAQ if you have any problems with the CodeChef judge system

Hi, I agree with Manu - the

ninjaflyte @ 24 Jul 2010 10:31 PM
Hi, I agree with Manu - the sample test case should have 1 as the answer. "...with the bottom-left corner at (0,0) and top-right corner at (w,h)..." So the matrix looks like this: 0 0 0 4 0 0 0 1 0 0 0 0 2 5 0 0 0 0 0 0 And hence, the best possible case would be to place the center at (1,2). Right?

what does it mean when they

lmconline @ 24 Jul 2010 10:33 PM

what does it mean when they say first line

do we have to read a line and then scan respective values of variables from it or scan values for each variable one by one

and why do we get runtime error (other)

it says in faq that it is due to too much memory but my result shows 1.6 m while many currect submissions are showing 17,30,18m ?

please help

"...with the bottom-left

ninjaflyte @ 24 Jul 2010 10:35 PM

"...with the bottom-left corner at (0,0) and top-right corner at (w,h).."

Taking this into consideration, the answer should be 1 to the test case.

@admin: pls check.


@Karthik: The statement said

anhdq_adm @ 24 Jul 2010 10:40 PM

@Karthik: The statement said "The office may only be built once all points it covers (including the boundaries) are free of barricades." so if you put a square centering at (1, 2), you must still remove the baricade at (2, 1) which costs 2, ok ?

@lalit mohan chawla: please see the FAQ for the instructions of i/o :-) the statement is clear.
not only overflowing memory causes runtime error, please check your code again ;)

@Karthik: (again) please

anhdq_adm @ 24 Jul 2010 10:42 PM

@Karthik: (again) please check the problem statement again, you may misunderstand somewhere :-)

how large can the inputs

indraneel @ 24 Jul 2010 10:55 PM

how large can the inputs be?
any ranges?
can we consider all as unsigned integers?

@Indraneel P: please check

anhdq_adm @ 24 Jul 2010 10:58 PM

@Indraneel P: please check the limitations part for details, all are clear ;-)

OOPS........ 2min late to

indraneel @ 25 Jul 2010 12:05 AM

OOPS........

2min late to submit! :(

when will this be posted to

indraneel @ 25 Jul 2010 12:07 AM

when will this be posted to practice problems?
I wan't to check whether my solution is correct.

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