fack's blog

By fack, history, 5 weeks ago, In English,

Suppose I have a weighted graph with equal positive weight (let it be K) on each edge. Now I want to count the number of ways to assign weights to vertices SUCH THAT if there is an edge between X and Y then max(W[X], W[Y])=K where W[X] means assigned weight to vertex X.

can someone solve it in better than O(2^n).

Anyone could help me with LCM constrainsts. Please DM

Thanks

 
 
 
 
  • Vote: I like it
  • -18
  • Vote: I do not like it

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been updated by fack (previous revision, new revision, compare).

  • »
    »
    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The best I could come up is O(2^n)

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Note that for K = 2 this problem is equivalent to finding the number of vertex covers, which is #P-hard.

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Even the special case of this problem $$$K=2$$$ (equivalent to counting vertex covers) is #P-complete, because counting solutions to 2-SAT is also #P-complete, and a vertex cover can easily be represented with a 2-SAT formula.

»
5 weeks ago, # |
  Vote: I like it +22 Vote: I do not like it

Heh, ongoing codechef again. And this is even not exactly correct reduction. Why dont they learn?..

  • »
    »
    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I guess my reduction is correct as I am able to get ac for N=20 cases

  • »
    »
    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Anyone willing to help in LCM constraints Please DM

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been updated by fack (previous revision, new revision, compare).

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been updated by fack (previous revision, new revision, compare).

»
5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

are koi to batado bhai intern start hone wali h batado.. 5 star ban jayege... O(2^n) me to ho gya.

  • »
    »
    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    but 30 and 38 wale testcases ke liye nahi hora DM stardo approch

    • »
      »
      »
      5 weeks ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      yaar ye recent action me upper kyo nahi aara? anyone?