QTREE2 - Query on a tree II
You are given a tree (an undirected acyclic connected graph) with N nodes, and edges numbered 1, 2, 3 ...N-1. Each edge has an integer value assigned to it, representing its length.
We will ask you to perform some instructions of the following form:
- DIST a b : ask for the distance between node a and node b
or - KTH a b k : ask for the k-th node on the path from node a to node b
Example:
N = 6
1 2 1 // edge connects node 1 and node 2 has cost 1
2 4 1
2 5 2
1 3 1
3 6 2
Path from node 4 to node 6 is 4 → 2 → 1 → 3 → 6
DIST 4 6 : answer is 5 (1 + 1 + 1 + 2 = 5)
KTH 4 6 4 : answer is 3 (the 4-th node on the path from node 4 to node 6 is 3)
Input
The first line of input contains an integer t, the number of test cases (t <= 25). t test cases follow.
For each test case:
- In the first line there is an integer N (N <= 10000)
- In the next N-1 lines, the i-th line describes the i-th edge: a line with three integers a b c denotes an edge between a, b of cost c (c <= 100000)
- The next lines contain instructions "DIST a b" or "KTH a b k"
- The end of each test case is signified by the string "DONE".
There is one blank line between successive tests.
Output
For each "DIST" or "KTH" operation, write one integer representing its result.
Print one blank line after each test.
Example
Input: 1 6 1 2 1 2 4 1 2 5 2 1 3 1 3 6 2 DIST 4 6 KTH 4 6 4 DONE Output: 5 3
hide comments
cokalhado:
2024-08-24 20:10:06
I just spent a whole hour to figure out I'd done (a << i) instead of (1 << i) when doing the binary lifting :( |
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pb2008:
2024-07-27 13:36:35
use tarnary lifting + log decomposition
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king_87arshia:
2024-07-27 13:35:49
use sqrt decomposition + sparse desk |
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satyam1722:
2024-05-28 20:04:44
i am getting the wrong answer but i dont know why
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riaj_123:
2023-10-02 16:48:05
Very easy just LCA
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baodepzai:
2023-09-14 10:16:47
easy one |
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metalavocado99:
2023-05-23 10:59:23
DANG , this sounds hard as hell |
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ahmed_bahu:
2022-08-18 07:28:51
what is the root of the tree ?
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outcast0216:
2021-11-08 14:37:28
How can I get the data of this problem ?
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ppap_1264589:
2021-09-15 19:04:07
If you use LCA for this problem, remember to check if 'a' and 'b' in a same branch and 'a' is closer to the root than 'b'
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Added by: | Thanh-Vy Hua |
Date: | 2006-08-27 |
Time limit: | 1s |
Source limit: | 15000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL JS-RHINO NODEJS PERL6 VB.NET |
Resource: | Special thanks to Ivan Krasilnikov for his alternative solution |