ToErr's blog

why priority_queue is not behaving as expected?
By ToErr, history, 6 years ago, In English

this submission using priority_queue is giving TLE : http://mirror.codeforces.com/contest/467/submission/43003735

where using set giving AC : http://mirror.codeforces.com/contest/467/submission/43003953

problem link: http://mirror.codeforces.com/contest/467/problem/D

could anyone point me out what is wrong here! i am literally not getting the point :(

  • Vote: I like it
  • -15
  • Vote: I do not like it

»
6 years ago, # |
  Vote: I like it +4 Vote: I do not like it

I think you need to check whether not-unique items being inserting into container or not.

set keeps only unique items. priorityqueue doesn't. Therefore you can execute for-loop inside while-loop too many extra times and get TLE.

→ Reply
  • »
    »
    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like it

    yes, thank you for pointing it out.

    it is giving time limit for this 'non-unique' pushing.

    if the edges are like:

    1-x

    2-x

    ...

    ...

    ...

    n-x

    then x will be pushed n times in the queue,which will lead the complexity to O(n^2).

    it is sad that i have missed the point.

    again thank you for pointing this.

    → Reply