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Need help with UVA — 10218 — Let's Dance

Revision en2, by Bekh, 2019-02-12 20:47:19

Hello,

Here's the problem link: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1159

I know and already got AC with other, but I was trying various dp states/approaches for practice. I wanted to know what I am missing in this dp approach since I'm getting a bit lower value than the sample output (0.5012511 instead of 0.5002286)

Solution link: https://ideone.com/AjdoVF

approach: * i is zero based

  • Dp definition:

  • dp[i][rem] is probability to get a final even 'usedCandy' count in range [i, m) using 'rem' candies such that usedCandy = totalCandies — rem

  • base case:

  • at i == m, return isEven(usedCandy)

  • transition:

  • at each [i][rem], if 'tk' is amount given to man 'i'. 'tk' is in [0, rem]

  • answer = Summation for all 'tk' in [0, rem] -> P(man 'i' getting exactly tk candies) * dp[i + 1][rem — tk]

  • P(a man getting exactly 'tk' candies) having 'rem' candies in total can be found through binomial theorom C[rem][tk] * p^tk q^(rem — tk) such that p is probability for

  • a person to get a single candy = 1/(m+w) and q = 1 — p

If something is not clear with my solution, please ask. Where am I going wrong with this dp?

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en5 English Bekh 2019-02-12 20:54:52 17 Tiny change: 'with other, but I wa' -> 'with other neater solutions, but I wa'
en4 English Bekh 2019-02-12 20:48:25 9
en3 English Bekh 2019-02-12 20:47:36 2 Tiny change: 'proach: \n * i is ' -> 'proach: \n\n * i is '
en2 English Bekh 2019-02-12 20:47:19 26
en1 English Bekh 2019-02-12 20:46:16 1279 Initial revision (published)