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
- QUERY a b : ask for the maximum edge cost on the path from node a to node b
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.
For each "QUERY" operation, write one integer representing its result.
Input: 1 3 1 2 1 2 3 2 QUERY 1 2 CHANGE 1 3 QUERY 1 2 DONE Output: 1 3
呔！Last edit: 2015-04-14 14:11:26
I have got Accepted!Last edit: 2015-04-01 03:09:30
very good problem.
I got WA
This problem is so good!My program is accpeted!But I want to know how to solve it by link cut tree.Who can help me?
Don't use string and cin for the words in input --> will cause TLE. Use char array and scanf instead. Wasted 4 hours on such a stupid issue.Last edit: 2014-12-28 16:58:25
My solution, complexity O(logn ^2) for each "query" and O(logn) for each "Change"??? Is the time limit so low ??Last edit: 2014-10-30 22:54:43
How many queries are there at most?
|Added by:||Thanh-Vy Hua|
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