Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Arun
Isnt it running DFS on every node? 1) Pick any node in the graph say n 2) With n as root, run DFS. While running DFS, if you visit node x, mark M[n,x]=1 and M[x,n]=1 (since its unidirected graph, M[i,j] will be equal to M[j,i] for any j,i) . The running time is O(k) where k is the number of nodes

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
Isnt it running DFS on every node? 1) Pick any node in the graph say n 2) With n as root, run DFS. While running DFS, if you visit node x, mark M[n,x]=1 and M[x,n]=1 . The running time is O(k+E) [not k, you are forgetting the case when E != O(n)] .Also have a hash finished[n]=true. 3) Repeat steps

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
On Tue, Nov 24, 2009 at 1:48 PM, Arun arunm...@gmail.com wrote: Isnt it running DFS on every node? 1) Pick any node in the graph say n 2) With n as root, run DFS. While running DFS, if you visit node x, mark M[n,x]=1 and M[x,n]=1 (since its unidirected graph, M[i,j] will be equal to M[j,i]

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
it is what the question says.. and that's why the question is here right? -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to algoge...@googlegroups.com. To unsubscribe from this group, send email to

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
You just need to run DFS once. It will give you all the connected components. So it is indeed O(n+e) On Tue, Nov 24, 2009 at 2:43 PM, Rohit Saraf rohit.kumar.sa...@gmail.comwrote: Isnt it running DFS on every node? 1) Pick any node in the graph say n 2) With n as root, run DFS. While running

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
COMPUTE (x,y) { if(matrix[x][y] != EMPTY) return matrix[x][y]; for all k in 1:N if(COMPUTE(x,k)COMPUTE(k,y)) matrix[x][y]=1; EXIT endfor matrix[x][y]=0; } CLOSURE (M){ //M is the matrix for all i,j s.t matrix[x][y]=EMPTY

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
Hi, On Tue, Nov 24, 2009 at 3:09 PM, Rohit Saraf rohit.kumar.sa...@gmail.comwrote: it is what the question says.. and that's why the question is here right? Could you clarify what the question asks please. Does it want you to get the connected components? Or does it want you propose a data

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
COMPUTE (x,y) { if(matrix[x][y] != EMPTY) return matrix[x][y]; for all k in 1:N if(COMPUTE(x,k)COMPUTE(k,y)) matrix[x][y]=matrix[y][x]=1; EXIT endfor matrix[x][y]=0; } CLOSURE (M){ //M is the matrix for all i,j s.t matrix[x][y]=EMPTY

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
You are given a graph G. if there exists a path from ai to aj in G, then store in matrix CLOSUREMATRIX[i][j]=1 You have to find connectivity between all pairs. is it clear now? -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this

[algogeeks] Search in a sorted NxN matrix

2009-11-24 Thread Rohit Saraf
A nice problem that i encountered : In O(n) search for a value x in a sorted NxN matrix. Definition of sorted matrix: All rows and all columns are sorted in ascending order. So thought of sharing .. Rohit Saraf Sophomore Computer Science and Engineering IIT Bombay -- You received this

Re: [algogeeks] Algorithm for vector problem

2009-11-24 Thread Aditya Shankar
Hi, On Tue, Nov 24, 2009 at 6:38 PM, Ankur ankuraror...@gmail.com wrote: What would be the best algorithm for the undermentioned problem. Implement method PrintFamilyTree() that prints out the Name and Generation of the tree Output should resemble Name: Jan Generation:0 Name: Mike

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
On Tue, Nov 24, 2009 at 3:21 PM, Rohit Saraf rohit.kumar.sa...@gmail.comwrote: @aditya: If you run DFS once.. you can in O(1) decide whether a point is connected to the root of dfs tree. but not with other points. It is an undirected graph right? So, you can go from node A to

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Rohit Saraf
But then .. think.. for every two pairs of nodes you have to check whether both are connected to root and then you will say yes/no. And you will have to do this for all disjoint components. It's right but not O(n^2). -- You received this message because you are subscribed to the Google Groups

Re: [algogeeks] Search in a sorted NxN matrix

2009-11-24 Thread chitta koushik
Start from top right or bottom left corner and move according if the element to be searched is lesser or greater than current. --Koushik C Pablo Picassohttp://www.brainyquote.com/quotes/authors/p/pablo_picasso.html - Computers are useless. They can only give you answers. On Tue, Nov 24, 2009

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
Hi, What I am trying to say is this. a. Do a DFS on the given graph G to get connected components C1...Ck b. Consider Ci (i) I claim that every pair of nodes in the connected component is connected to every other node in the same connected component (say you have arbitrary points A,B in Ci,

[algogeeks] how can i find size of an object in java

2009-11-24 Thread Abhijeet Kumar
How can i find size of an object in java plsss answer asap -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to algoge...@googlegroups.com. To unsubscribe from this group, send email to

Re: [algogeeks] how can i find size of an object in java

2009-11-24 Thread Chakravarthi Muppalla
measure jvm memory usage before/after creating ur object; but it is not assured to give the correct size(gc). or u can use a premain agent. On Wed, Nov 25, 2009 at 12:37 AM, Abhijeet Kumar abhijeet.k.s...@gmail.comwrote: How can i find size of an object in java plsss answer asap -- You

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Chakravarthi Muppalla
as long as it is an undirected graph;simple dfs would suffice! On Tue, Nov 24, 2009 at 10:13 PM, Rohit Saraf rohit.kumar.sa...@gmail.comwrote: But then .. think.. for every two pairs of nodes you have to check whether both are connected to root and then you will say yes/no. And you will

Re: [algogeeks] Transitive Closure of a Undirected graph

2009-11-24 Thread Aditya Shankar
On Tue, Nov 24, 2009 at 10:46 PM, Rohit Saraf rohit.kumar.sa...@gmail.comwrote: i had already understood what you claimed But MY CLAIM: every pair of nodes in the connected component is connected to every other node in the same connected component. U CANNOT UPDATE ALL THE PAIRS AS EASILY AS

Re: [algogeeks] Algorithm for vector problem

2009-11-24 Thread Algoose Chase
void PrintFamilyTree(const short generation) { printf(Name : %s Generation = %d\n, m_Name.c_str(),generation); vectorHuman*::iterator it; for (it = this.begin(); it this.end() ;it++) { it-PrintFamilyTree(generation+1); } } On Tue, Nov 24, 2009 at 9:20 PM, Aditya Shankar