539 - The Settlers of Catan

All about problems in Volume 5. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

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russoue
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Location: Bangladesh

539 - The Settlers of Catan

Post by russoue »

Can anyone tell me what is the problem with my code? I think I got it right but am getting WA.
Please I need help.
Thanks in advance


[c]#include <stdio.h>

int n, m, max;
int matrix[30][30];
int not_visited[30];
void dfsbt(int, int);

int main(void)
{
register int i, j;
int from, to;


scanf("%d %d", &n, &m);
while(n || m) {
for(i = 0; i < n; i++) {
for(j = 0; j < n; j++) {
matrix[j] = 0;
}
not_visited = 1;
}

for(i = 0; i < m; i++) {
scanf("%d %d", &from, &to);
matrix[from][to] = matrix[to][from] = 1;
}

max = 0;
for(i = 0; i < n; i++) {
if(not_visited) {
dfsbt(i, 0);
}
}
printf("%dn", max);
scanf("%d %d", &n, &m);
}

return 0;
}

void dfsbt(int node, int length)
{
register int i;

not_visited[node] = 0;
if(length > max)
max = length;

for(i = 0; i < n; i++) {
if(matrix[node]) {
matrix[node] = matrix[node] = 0;
dfsbt(i, length + 1);
matrix[node] = matrix[node] = 1;
}
}
}[/c]
Last edited by russoue on Thu May 02, 2002 12:30 pm, edited 1 time in total.

chang
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Posts: 16
Joined: Wed Jan 16, 2002 2:00 am

>>>>>>>>>>>>

Post by chang »

U forget to print '\n'....u print 'n'
another matter, i used dfs taking each node as starting node....I can't remember why i used so...if u get WA, u may modify it.....

russoue
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Joined: Sun Apr 07, 2002 2:00 am
Location: Bangladesh

Post by russoue »

Thanks for your reply.
Actually I was printing "\n" in my code but for unknown reason the '\' is not showing up here.

obayashi
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Posts: 33
Joined: Thu Jun 20, 2002 1:18 pm

Solution

Post by obayashi »

I've modified your code a little and merged with my code, then got AC...

The problem with your code lies in the varible "not_visited".

There's no need to use this varible to mark the node visited.

The problems just has something to do with the EDGE not the NODE.

So to mark the node is not reasonable.

Just leave out it and you will certainly get AC.

Good luck.

p.s. I've learned a lot from your code. Thanks indeed.
Time makes a fool of memory
And yet my memories still shine

New(User)
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Posts: 3
Joined: Sat Jan 31, 2004 11:01 am

539 what's the idea?

Post by New(User) »

what's the idea for this problem ?

i tried to do a modified dfs starting from each node and memorize the longest distance but i get time limit exceeded..

here's my code:
[pascal]
program settlers;
var mat,A:array [0..50,0..50] of integer;
max:integer;
n:integer;
procedure DF(i,l:integer);
var j:integer;
begin
if (l > max) then max:=L;
for j:=1 to N do
if A[i,j]=1 then begin
A[i,j]:=0;
A[j,i]:=0;
df(j,l+1);
A[i,j]:=1;
A[j,i]:=1;
end;
end;
procedure Solve;
var i:integer;
begin
max:=0;
for i:=0 to N do
begin
A:=mat;
DF(i,0);
end;
writeln(output,max);
end;
procedure fA(m:integer);
var x,y,i:integer;
begin
for i:=1 to m do
begin
readln(input,x,y);
mat[x,y]:=1;
mat[y,x]:=1;
end;
Solve;
end;
procedure fB;
var m:integer;
begin
readln(input,n,m);
while not ((m=0) and (n=0)) do
begin
fA(m);
readln(input,n,m);
end;
end;
begin
fB;
end.
[/pascal]

Experimenter
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Location: Russia

Post by Experimenter »

i can't believe i got accepted using brute force. :lol: :o :lol: what a bullshit. :D :o :o :lol:
it would be great if you replied this post. really.

Eduard
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Location: Armenia,Yerevan

Post by Eduard »

Hello New(User)
You have some mistakes in your code.
AT first after reading make n:=n-1.Then clean your mat array after each test case.In procedure DF make j:=0 to n do.
And you will get AC.If you will have WA tell me.
Eduard
someone who like to solve informatic problems.
http://acm.uva.es/cgi-bin/OnlineJudge?AuthorInfo:29650

yogeshgo05
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Posts: 47
Joined: Sun Nov 27, 2005 12:43 pm

539 why wa ..plz help

Post by yogeshgo05 »

hell guys ..
can anybody tell why wa.. i know backtrackin is quite okay....
here's my code....
Last edited by yogeshgo05 on Sun Feb 11, 2007 8:01 pm, edited 1 time in total.

helloneo
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Joined: Mon Jul 04, 2005 6:30 am
Location: Seoul, Korea

Post by helloneo »

There is a thread on this problem already.. plz use old thread to post..

I think these lines are located at a wrong place..

Code: Select all

(*count)++; 
...
...
v.push_back((*count)); 
(*count)--; 

yogeshgo05
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Posts: 47
Joined: Sun Nov 27, 2005 12:43 pm

Post by yogeshgo05 »

i have modified the code a bit i guess...
plz tell me why wa....
Last edited by yogeshgo05 on Sun Feb 11, 2007 8:01 pm, edited 1 time in total.

rio
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Joined: Thu Sep 21, 2006 5:01 pm
Location: Kyoto, Japan

Post by rio »

Try this test case. You'll know why WA.

Code: Select all

2 2
0 1
1 0
0 0
The answer should be 2.

ADD: Don't forget removing your code after AC.

soyoja
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Location: Seoul, South Korea
Contact:

Post by soyoja »

Additonal comment about rio's post. =)

It's an undirectional graph. threrfore, 0 -> 1 is same as 1 -> 0.
Good luck.
I love Problem Solving!!! :) :) :)

yogeshgo05
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Posts: 47
Joined: Sun Nov 27, 2005 12:43 pm

Post by yogeshgo05 »

hey that's rite...

then rio means

0 1
1 0

if the ans is 2
then
are two different undirected edges.....
that means there can many edges b/w the same two nodes....
so that resulting in first bactracking b/w the nodes...

rifayat samee_du
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Location: Beside you........

Re: 539 why wa ..plz help

Post by rifayat samee_du »

Hello rio??
there is no input like
2 2
0 1
1 0
Name : Sanzee
Location: In front of a x86 machine So...you never know may be beside you!!

Mukit Chowdhury
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Location: Dhaka
Contact:

Re: 539 why wa ..plz help

Post by Mukit Chowdhury »

got WA !!! please help me !!! give me some sample input !!!

Code: Select all

Deleted after accepted !!!!!!
Last edited by Mukit Chowdhury on Sat Oct 20, 2012 4:35 am, edited 1 time in total.

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