Tornad0's blog

By Tornad0, history, 8 years ago, In English

Hi all,

I have difficulty on a problem on codeforces http://mirror.codeforces.com/problemset/problem/691/D

my submission is : http://mirror.codeforces.com/contest/691/submission/19308291

I think my idea is right, I used dsu to group several numbers and downsort numbers inside the groups. But I don't know why I am still wrong answer at test21. The idea is simple, but I can't find what's wrong. Anyone please help me, thanks:D

How to find bugs when you think your algorithms and implementation is correct,BTW?

Edit: Bug found:)))

I should calculate p[i]=parent(i) before I use p[i] . I thought it was automatically done by merging, however it is not :DDDD

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8 years ago, # |
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Here is AC version of your submission. You should re-check the parent of every node.