[HN Gopher] Dynamic programming bursting balloons
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Dynamic programming bursting balloons
Author : ingve
Score : 7 points
Date : 2025-07-30 18:39 UTC (2 days ago)
(HTM) web link (sylhare.github.io)
(TXT) w3m dump (sylhare.github.io)
| jasonpeacock wrote:
| Am I completely misunderstanding the problem, or is the math in
| the example solution wrong? Bursting 1 first
| gives you 3x1x5=15 coins. <-- OK... Bursting 3 first
| gives you 1x3x1=1 coins. (using left virtual balloon) <-- Should
| be 3? A possibility would be bursting 1, then 5, then 3,
| which gives you a total of 3x1x5+3x5x1+1x3x1=33 coins. <-- Should
| be 3x1x5+1x5x1+1x3x1=24?
| mauricioc wrote:
| If you have "3 1 5" and you burst 1, you gain 3x1x5 points and
| the state becomes "3 5", with the two remaining balloons being
| adjacent to each other.
|
| The "1x3x1=1" part for the earlier example is a typo indeed, it
| should be 3.
| Jtsummers wrote:
| The first error seems to be a transcription error, it's correct
| in their graph representation further down.
|
| The second one isn't an error, but a poor explanation. After a
| balloon is burst, the balloons now have new neighbors. That is,
| it isn't this: 3 1 5 -> pop 1 = 15 3 _ 5
| -> pop 3 = 3
|
| It's: 3 1 5 -> pop 1 = 15 3 5 -> pop 3
| = 15
|
| The distance between the balloons doesn't make them not
| neighbors.
| SJC_Hacker wrote:
| This is fairly old Leetcode problem (who probably got it from
| somewhere else)
|
| https://leetcode.com/problems/burst-balloons/description/
|
| Its tricky and if I got this problem in a tech interview, I would
| be hard-pressed to solve it in 45 minutes if I hadn't seen it
| before
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