QTREE - Query on a tree


You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1.

We will ask you to perfrom some instructions of the following form:

  • CHANGE i ti : change the cost of the i-th edge to ti
    or
  • QUERY a b : ask for the maximum edge cost on the path from node a to node b

Input

The first line of input contains an integer t, the number of test cases (t <= 20). 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 <= 1000000),
  • The next lines contain instructions "CHANGE i ti" or "QUERY a b",
  • The end of each test case is signified by the string "DONE".

There is one blank line between successive tests.

Output

For each "QUERY" operation, write one integer representing its result.

Example

Input:
1

3
1 2 1
2 3 2
QUERY 1 2
CHANGE 1 3
QUERY 1 2
DONE

Output:
1
3

hide comments
mb81: 2018-07-30 08:45:48

BK

spojmaster_9: 2018-07-26 15:14:33

Finally, I did it, after 17 times

pshishod2645: 2018-07-24 16:41:37

Time limit is too strict.
. don't use c++ max function or preprocessor for max. Instead use if or ( ? : ;)
. use char s[], instead of c++ string

dynamite_iit: 2018-04-20 16:48:59

https://ideone.com/nYZ4ru
Cpp working Solution.

Last edit: 2018-04-20 16:56:55
lukamercep: 2018-04-01 14:52:54

Don't use c++ MIN and MAX functions from algorithm, they are very slow, us IF instead!

siva2697: 2018-02-23 17:59:22

Very Nice Problem Learnt New Concept C++ working LCA with DP too

Last edit: 2018-02-23 18:52:18
sagar2009kumsr: 2017-12-28 07:32:37

Is c++ solution is submitting on this ??

ganeshjadhav: 2017-12-25 19:11:29

Credit goes to Anudeep such a nice blog HLD+segment tree.

labo: 2017-09-06 20:51:43

Did anyone solve this in Python ? Get TLE with HLD…

coderbond007: 2017-07-10 17:24:42

Java got TLE. Same code in C++ passed. :(


Added by:Thanh-Vy Hua
Date:2005-06-08
Time limit:0.851s
Source limit:15000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
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