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
adam____:
2021-08-23 17:59:05
AC, but HLD is just pain |
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princemishra:
2021-02-16 17:20:28
best place to study heavy light decompostion
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whhsteven:
2020-08-30 16:16:41
Not kidding. What's HLD? Please tell me... Last edit: 2020-08-30 16:17:01 |
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mhasan01:
2020-07-09 23:14:38
Nice problem to learn HLD :) |
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pareksha:
2020-05-01 10:04:49
If you are getting RE SIGSEGV, use void return type with functions not returning anything. |
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an09mous:
2020-03-22 19:46:14
There's no need to find LCA separately if you are using HLD. |
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sangmai:
2020-02-18 05:18:44
I add ios_base::sync_with_stdio(false);cin.tie(NULL); and TLE becomes AC |
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fatnot:
2020-01-06 11:40:24
getting tle on cpp is that ok
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zer0_h6cks:
2019-12-05 10:34:33
See this as well.
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zufius:
2019-11-28 09:41:34
if you get TLE, just optimize function max, dfs & hld decomposition like this guy : https://ideone.com/Ykg63S
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Added by: | Thanh-Vy Hua |
Date: | 2005-06-08 |
Time limit: | 1s |
Source limit: | 15000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | ADA95 ASM32 BASH BF C CSHARP CPP CLPS LISP sbcl LISP clisp D FORTRAN HASK ICON ICK JAVA LUA NEM NICE OCAML PAS-GPC PAS-FPC PERL PHP PIKE PRLG-swi PYTHON RUBY SCM guile SCM qobi ST TEXT WHITESPACE |