AminAnvari's blog

LCA problems
By AminAnvari, 9 years ago, In English

Hi :)
These are some LCA (lowest common ancestor) problems. I hope you enjoy them.
I tried to sort them by difficulty. If you know more problems, add it to comments.

208E - Blood Cousins
191C - Fools and Roads
519E - A and B and Lecture Rooms
587C - Duff in the Army
609E - Minimum spanning tree for each edge
178B3 - Greedy Merchants
176E - Archaeology
466E - Information Graph

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Comments Comments (26)
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9 years ago, # |
  Vote: I like it +11 Vote: I do not like it

Hello, A Secret Mission — LOJ , Min Max Roads — LOJ , LCA — SPOJ , Kth Ancestor — HackerRank

Here I found a few LCA / LCA modifications :)

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    7 years ago, # ^ |
      Vote: I like it -6 Vote: I do not like it

    Some basic LCA problems? Which can be solved by only using LCA? By some I mean many please! O_o

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

Thank you so much for taking the time to compile all these lists.

I really appreciate your work!

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9 years ago, # |
  Vote: I like it +21 Vote: I do not like it

504E - Misha and LCP on Tree

LCA + hash

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

Thanks for gathering all problems with same tag!! I was looking for LCA ones :D

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9 years ago, # |
  Vote: I like it +11 Vote: I do not like it

Another LCA problmes:

Qtree spoj : LCA + Heavy-light Decomposition + segment tree

372D - Choosing Subtree is Fun : LCA + sorting + dfs(starting time calculating) + two_pointer (or Heavy-light Decomposition)

342E - Xenia and Tree : LCA + Sqrt Decomposition

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9 years ago, # |
  Vote: I like it +3 Vote: I do not like it

629E - Famil Door and Roads

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7 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

A great LCA problem from codechef : TOMJERGA

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7 years ago, # |
  Vote: I like it +9 Vote: I do not like it

916E - Jamie and Tree

the newest one :)

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6 years ago, # |
← Rev. 3   Vote: I like it 0 Vote: I do not like it

I wrote code for 191C but I got verdict: wrong answer on test 3. please, tell to me, why my code does not works correctly. link: https://codeforces.net/contest/191/submission/39604271

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6 years ago, # |
  Vote: I like it +3 Vote: I do not like it

986E - Prince's Problem

Nice problem :)

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6 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

http://www.spoj.com/problems/DISQUERY/ this is problem based only on LCA. this problem is from the SPOJ. update: this problem is not based only on lca, sorry for mistake.

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6 years ago, # |
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https://codeforces.net/contest/1062/problem/E Nice LCA problem ^_^

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6 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

https://www.hackerrank.com/contests/101hack26/challenges/sherlock-and-queries-on-the-graph (LCA + Bridge finding) :) and thank you so much for your list

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6 years ago, # |
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Two easy ones and a harder one

Kattis — tourists Kattis — boxes Kattis — pokegene

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5 years ago, # |
  Vote: I like it -22 Vote: I do not like it

Thanks for these problem list and i was waited for this

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

this problem from a recent round

1-Trees and Queries

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5 years ago, # |
  Vote: I like it +9 Vote: I do not like it

https://codeforces.net/contest/1328/problem/E

in the recently contest

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4 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

csacademy's Identifying-Infected is a LCA tagged problem. How to approach this? Sorry for necro-bumping.

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    4 years ago, # ^ |
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    Answer is the number of cut vertices on the simple path between query vertices in the Block-Cut Tree of the graph. This can be found in logN time by calculating the LCA of the Block-Cut Tree.

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2 years ago, # |
← Rev. 4   Vote: I like it +5 Vote: I do not like it

LCA problem from the contest just now codeforces.com/contest/1702/problem/G2

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2 years ago, # |
← Rev. 2   Vote: I like it +3 Vote: I do not like it

Highly recommend))) 786D - Rap God

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