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
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. :(

ankit mathur: 2017-07-08 20:03:34

what the fuck...submitted same code 3 times...1 time it got accepted...2 times it got tle...what the fuck spoj..

kr_abhinav: 2017-07-07 10:10:40

Guys try to avoid LCA using dp, try doing it with HLD itself, took me 9 submissions to AC

Harish Chandra Thuwal: 2017-07-05 14:08:07

Hi can anyone explain how the LCA is implemented in anudeep's (HLD code)blog ?

sultania23: 2017-06-27 15:50:09

HLD + segment tree . do read HLD from anudeep's blog.

sjp_32123: 2017-06-27 09:23:10

my code is getting complied in codeblocks but when i submit it here its showing compilation error.......??? I use c++

Last edit: 2017-06-27 09:23:32
67890: 2017-01-12 08:47:08

Did you talk something about my username?⊙▂⊙ @hld67890

fanatique: 2016-11-24 19:43:49

HLD + segment tree... spent lot of time on debugging :(

brainf_ck: 2016-09-19 00:10:23

Nice problem for HLD, thanks AnuDeep!

Last edit: 2016-09-19 06:04:18

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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