10004 - Bicoloring

All about problems in Volume 100. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

Moderator: Board moderators

Ron
Learning poster
Posts: 55
Joined: Mon Jul 23, 2007 5:01 pm
Location: INDIA

Post by Ron » Fri Aug 03, 2007 9:01 am

please !! check the above program , and reply me any test cases , for what my program is wrong.............

User avatar
rio
A great helper
Posts: 385
Joined: Thu Sep 21, 2006 5:01 pm
Location: Kyoto, Japan

Post by rio » Fri Aug 03, 2007 9:25 am

I can't understand your program well. Could you give a brief explanation of you algorithm ?
Then it well be much more easier to understand and debug.

EDIT : When you post your code, use Code tags.

EDIT : OK. I understood your algorithm. Actually its not correct. I'll make a critical test case.
----
Rio

User avatar
rio
A great helper
Posts: 385
Joined: Thu Sep 21, 2006 5:01 pm
Location: Kyoto, Japan

Post by rio » Fri Aug 03, 2007 9:57 am

Try this case:

Code: Select all

4
3
0 3
1 2
2 3
0
Its obviously bicolorable.
----
Rio

Ron
Learning poster
Posts: 55
Joined: Mon Jul 23, 2007 5:01 pm
Location: INDIA

Post by Ron » Fri Aug 03, 2007 10:08 am

Thank you very much .. :D Rio !!!

User avatar
Fuad Hassan EWU
New poster
Posts: 38
Joined: Tue Jul 17, 2007 3:21 pm
Location: East West University

TLE

Post by Fuad Hassan EWU » Sat Feb 02, 2008 11:14 pm

HI i am having TLE in this prob, can u plz help?

AC
Eagle er moto daana meley urbo

User avatar
newton
Experienced poster
Posts: 162
Joined: Thu Jul 13, 2006 7:07 am
Location: Campus Area. Dhaka.Bangladesh
Contact:

Re: 10004 - Bicoloring WA

Post by newton » Mon Sep 22, 2008 10:24 pm

Fuad Hassan EW

what was your algorithm?
you can place your code.

empo
New poster
Posts: 19
Joined: Mon Jul 28, 2008 7:00 pm
Location: India

Re: 10004 - Bicoloring

Post by empo » Fri Dec 12, 2008 11:47 am

At lastttttttttt GOT ACCEPTED yeyeye:
My Algo:Using like floyd Warshall starting from any first vertex(let A)...color it 1...take all of its adjacent(let B,C) ..(Now i will color all adjacent of A to -1 but i will have to check a condition that after coloring any adjacent of -1 color should not have -1 color)...for that now taking first adjacent(B) check all adjacent of that adjacent(B)..let(D,E) if anyone of D or E has the same color(-1) ..then it means graph is not bicolorable else if all conditions gaot satisfied for all vertex IT is biclorable...
"Accepted" is my passion but RTE is my weakness.....

asqwzxdfercv
New poster
Posts: 3
Joined: Sat May 16, 2009 3:40 am

Re: 10004 - Bicoloring

Post by asqwzxdfercv » Thu Jun 18, 2009 10:44 am

Below is my code. What is the problem :(

Code: Select all

spelling mistake. lol

Angeh
Experienced poster
Posts: 108
Joined: Sat Aug 08, 2009 2:53 pm

Re: 10004 - Bicoloring

Post by Angeh » Fri Aug 28, 2009 10:32 pm

Can Sombody help me with my WA!!

Code: Select all

 GoT AC --
Dont Forget The dot at the end of your Lines 
>>>>>>>>> A2
Beliefs are not facts, believe what you need to believe;)

asif_khan_ak_07
New poster
Posts: 25
Joined: Fri Apr 17, 2009 8:24 am

Re: 10004 - Bicoloring

Post by asif_khan_ak_07 » Mon Sep 28, 2009 7:58 am

I am getting WA in this problem....please help

Code: Select all

#include<stdio.h>
#include<queue>
#define  MAX 201
using namespace std;

queue<int>ans;
int n,e;
int path[MAX][MAX];
int col[MAX];



void ini(){
	for(int i=0;i<MAX;i++){
		for(int j=0;j<MAX;j++)
			path[i][j]=0;
		col[i]=0;
	}


}


int bfs(int u){
	int temp;
	ans.push(u);
	col[u]=1;
	while(!ans.empty()){
		temp=ans.front();
		ans.pop();
		for(int i=0;i<n;i++){
			if(path[temp][i]==1){
				if(col[i]==0){
					ans.push(i);
					if(col[temp]==1)
						col[i]=2;
					else
						col[i]=1;
				}
				
				else if(col[i]==col[temp])
					return 0;
			
			
			}
		}
	}

	return 1;
}


int main(){
	freopen("1004.txt","r",stdin);
	int a,b,val;
	while((scanf("%d",&n)==1)){
		if(n==0)
			break;
		scanf("%d",&e);
		ini();
		for(int i=0;i<e;i++){
			scanf("%d %d",&a,&b);
			path[a][b]=path[b][a]=1;
		}
		
		if(e>0)
		val=bfs(a);
		else
			val=1;
		if(val==0)
			printf("NOT BICOLORABLE.\n");
		else
			printf("BICOLORABLE.\n");

			
	}
	


return 0;
}

arifcsecu
Learning poster
Posts: 64
Joined: Fri Sep 25, 2009 11:29 am
Location: Chittagong,University of chittagong
Contact:

Re: 10004 - Bicoloring

Post by arifcsecu » Wed Oct 14, 2009 8:10 pm

" freopen("1004.txt","r",stdin);
int a,b,val;
while((scanf("%d",&n)==1)){
if(n==0)

"




your program reads input from a file
how can it possible
just comment the line like
// freopen("1004.txt","r",stdin)
Try to catch fish rather than asking for some fishes.

valkov
New poster
Posts: 20
Joined: Tue Jul 20, 2010 3:11 pm

Re: 10004 - Bicoloring

Post by valkov » Sat Aug 14, 2010 8:57 pm

Just got AC on this problem. Some tips:
1. Don't assume that there will be node 0, so don't start your BFS at node 0, use other trick :)
2.

Code: Select all

   Color the starting node ( passed to your BFS func ) with color 1 and enqueue it
    for each adjacent node 
        if not visited already
            mark visited            
            color it with the opposite of the parent color
            enqueue it
        else 
            if parentColor == currentNodeColor
               "NOT BICOLORABLE."
    "BICOLORABLE."

asraful.ruet
New poster
Posts: 5
Joined: Wed Aug 11, 2010 8:52 am

Re: 10004 - Bicoloring

Post by asraful.ruet » Sun Sep 12, 2010 6:11 am

I am asraful .
I tried to solve 10004
But i am getting WA .
Please help !

Here is my code ...

Code: Select all


#include<stdio.h>

int main(){

    int m[203][203],a[203],d[203],p[5],l,e,n,i,j,k;
     char c[203];

while(scanf("%d",&n) && n){


for(i=0;i<203;++i)
for(j=0;j<203;++j)
   m[i][j]=0;

for(i=0;i<203;++i)
 {
 a[i]=i;
 c[i]='Z';
 d[i]=0;
 }

for(i=0;i<5;i++)
 p[i]=0;



 scanf("%d",&e);

for(i=1;i<=e;++i){
  scanf("%d%d",&j,&k);
  m[j][k]=m[k][j]=1;
 }


for(i=0;i<n;++i){
     k=0;
for(j=0;j<n;++j)
  if(m[i][j]==1)
     ++k;
     d[i]=k;
}


for(i=0;i<n-1;++i)
 for(j=i+1;j<n;++j)
    if(d[i]<d[j]){
      k=d[i];
      d[i]=d[j];
      d[j]=k;
      k=a[i];
      a[i]=a[j];
      a[j]=k;
    }


                    // /* Coloring *///

 l=0;
 c[a[0]]='A';

 for(i=0;i<n;++i){
    if(c[a[i]]=='Z'){
       for(j=0;j<n;++j)
         if(m[a[i]][j]==1){
           if(c[j]!='Z'){
             p[c[j]-'A']=1;
            }
        }

      j=0;
      for(k=0;k<4;k++){
       if(p[k]==0&&j==0){
         if(k==0)
           c[a[i]]='A';
         else if(k==1)
           c[a[i]]='B';
         else if(k==2)
           c[a[i]]='C';
         else
           c[a[i]]='D';
             j=1;
           }
            p[k]=0;
          }
       }

   for(l=0;l<n;++l)
      if(m[a[i]][l]==1){

   if(c[l]=='Z'){
     for(j=0;j<n;++j)
        if(m[l][j]==1){
          if(c[j]!='Z'){
            p[c[j]-'A']=1;
             }
      }

      j=0;
      for(k=0;k<4;k++){
        if(p[k]==0&&j==0){
          if(k==0)
            c[l]='A';
          else if(k==1)
            c[l]='B';
          else if(k==2)
            c[l]='C';
          else
            c[l]='D';
          j=1;
         }
        p[k]=0;
      }
    }
  }
}

                   // Bicoloring ? //

 l=0;
 for(i=0;i<n;++i)
  if(c[i]=='C' || c[i]=='D')
    { l=1; break; }


if(l==0)
 printf("BICOLORABLE.\n");
else
 printf("NOT BICOLORABLE.\n");


}

 return 0;
}


abid_iut
Learning poster
Posts: 82
Joined: Wed Jul 16, 2008 7:34 am

Re: 10004 - Bicoloring WA

Post by abid_iut » Fri Apr 08, 2011 12:26 pm

my problem gives me correct output for all possible input given in different threads, but it is WA. what is the problem can anyone tell me please...
here is the code

Code: Select all

#include<iostream>
#include<cstdio>
#include<queue>
#define MAX 201
using namespace std;

queue<int>que;
int n,m;
int path[MAX][MAX];
int color[MAX];

void initialize(){
	int i,j;
	for(i=0; i<MAX; i++){
		for(j=0; j<MAX; j++){
			path[i][j] = 0;
		}
		color[i] = 0;
	}
}

int bfs(int u){
	int temp;
	int i;
	que.push(u);
	color[u] = 1;
	while(!que.empty()){
		temp = que.front();
		que.pop();
		for(i=0; i<n; i++){
			if(path[temp][i]==1){
				if(color[i]==0){
					que.push(i);
					if(color[temp] == 1)
						color[i] = 2;
					else color[i] = 1;
				}
				else if(color[i] == color[temp])
					return 0;
			}
		}
	}
	return 1;
}


int main(){
	int a,b,i,value;
	//freopen("10004.txt","r",stdin);
	while(scanf("%d",&n)==1&&n){
		scanf("%d",&m);
		initialize();
		for(i=0; i<m; i++){
			scanf("%d %d",&a,&b);
			path[a][b] = path[b][a] = 1;
		}
		if(m>0)
			value = bfs(a);
		else 
			value = 1;

		if(value==0)printf("NOT BICOLORABLE.\n");
		else printf("BICOLORABLE.\n");
	}
	return 0;
}

i love to wait... wait for better... and better will come...
http://akanoi.webs.com/

victorhugo
New poster
Posts: 1
Joined: Tue Jul 26, 2011 1:08 am

Re: 10004 - Bicoloring - Runtime Error

Post by victorhugo » Tue Jul 26, 2011 2:13 am

My solution is getting Runtime Error in 0.000s, but it works for all instances I've found in this board.
I don't know what is wrong. Is there a special test case that my code is not ready for?

Here is my code:

Code: Select all

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <cstring>

using namespace std;

#define MAX_V   205
#define RED     0
#define BLACK	1
#define EMPTY  -1

vector<int> colors(MAX_V, EMPTY);
vector<int> grafo[MAX_V];	/* lista de adjacencias */

void reset()
{
  for (int i = 0; i < MAX_V; i++)
    {
      colors[i] = EMPTY;
      grafo[i].clear();
    }
}
  
int coloring(int v, int cor)
{
  int anticor = 1-cor;
  colors[v] = anticor;

  vector<int>::iterator it;
  for (it = grafo[v].begin(); it != grafo[v].end(); it++)
    {
      if (colors[*it] == EMPTY)
	{
	  if (coloring(grafo[v][*it], anticor) == 0)
	    return 0;
	}
      else if (colors[*it] == anticor) return 0;
    }

  return 1;
}

int main(int argc, char** argv)
{
  int	n_vertices, n_arestas;  /* number of vertices and arestas */
  int	x, y;			
  int   is_bicolor; 
  
  while (1)
    {
      cin >> n_vertices;
      if (n_vertices == 0) break;

      cin >> n_arestas;

      reset();
      
      while (n_arestas--)
      	{
	  cin >> x >> y;
	  grafo[x].push_back(y);
	  grafo[y].push_back(x);
	}
      
      /* verifica se eh bicolor */
      colors[0] = BLACK;
      for (int i = 0; i < grafo[0].size(); i++)
	if (colors[i] == EMPTY)
	  is_bicolor = coloring(i, BLACK);

      if (is_bicolor)
	cout << "BICOLORABLE." << endl;
      else
	cout << "NOT BICOLORABLE." << endl;
    }

  return 0;
}
Thanks in advance.

Post Reply

Return to “Volume 100 (10000-10099)”