graph - Partition a Binary Tree into two tree such that the difference of their diameter is less than a specific value K -


given binary tree. have remove edge , partition two trees such difference of diameter of 2 new trees less specified value k.

i have naive solution picks each edge , checks condition if removing edge can obtain solution or not (we can using 2 dfs/bfs , calculate diameter). makes solution o(n^2).

can suggest me better approach mine?

i think can use dynamic programing this, unable visualize it.

it enough each node calculate height of tree below it. leaf node 0, , other nodes max(height of children) + 1. done tree post-order traversing.

diameter of binary tree height of left child + height of right child + 1. general trees (sum of 2 max heights) + 1.

idea of algorithm start root , 'climb down' higher child, while checking difference between diameter of child's subtree , rest of tree. can done calculated heights.

update

 root  / \ l   r

in tree, diameter pass through root node, or in 1 of subtrees. that:

root.diameter = max(l.height + r.height + 2, l.diameter, r.diameter).

if cut edge, e.g. edge between n , n.l:

  root   /  \  ...  ...   |   n  / \ l   r

l subtree has diameter upper formula. rest of tree has diameter

max(r.height + length(r, root) + root.height, root.r.diameter, r.diameter).

terms r.height , r.diameter depends on edge want check. terms root.height , root.r.diameter static while checking edges in root.l subtree (and vice verse). term length(r, root) depends on edge depth root, easy track.

with possible create method recursively checks cuts on 1 subtree edges.


Comments

Post a Comment

Popular posts from this blog

How to understand 2 main() functions after using uftrace to profile the C++ program? -

i trying uftrace profile following simple c++ program: #include <iostream> class { public: a() {std::cout << "a created" << std::endl;} ~a() {std::cout << "a destroyed" << std::endl;} }; int main() { a; return 0; } the profile result this: # uftrace a.out created destroyed # duration tid function 2.026 [ 4828] | __cxa_atexit(); [ 4828] | main() { [ 4828] | __static_initialization_and_destruction_0() { 89.397 [ 4828] | std::ios_base::init::init(); 0.768 [ 4828] | __cxa_atexit(); 93.029 [ 4828] | } /* __static_initialization_and_destruction_0 */ 94.425 [ 4828] | } /* main */ [ 4828] | main() { [ 4828] | a::a() { 11.104 [ 4828] | std::operator <<(); 10.825 [ 4828] | std::basic_ostream::operator <<(); 24.514 [ 4828] | } /* a::a */ [ 4828] | a::~a() { 0.978 [ 4828] | ...
Read more

c# - Update a combobox from a presenter (MVP) -

i using mvp in project, new in mvp. have 2 comboboxes. when select option in combobox, combobox should filled new data. this action in presenter. view 'view1' in presenter, , introduced combobox1 , combobox2 properties in 'view1', because need 'datasource', 'displaymember', 'valuemember' , 'refresh()' in method below. but, when using pattern, enough send property like public string combobox2 { { return combobox1.selectedvalue.tosstring(); } } into presenter not whole combobox. how can solve problem? public void onselectedindexchangedcombobox1() { if (view1.combobox1.selectedindex == -1) { return; } datatable dt = tools.getdatatable("a path"); var query = (from o in dt.asenumerable() o.field<string>("afield") == farmerview.combobox1.selectedvalue.tostring() orderby o.field<string>("anotherfield") select...
Read more

How to put a lock and transaction on table using spring 4 or above using jdbcTemplate and annotations like @Transactional? -

i trying put lock on table while writing on table , if happened in between roll-back . trying convert below code lock table test_g1 read; lock table test_g write; -- begin; start transaction; insert test_g1 values(143); insert test_g values(145); select * test_g1; select * test_g; rollback; select * test_g; unlock tables; how convert above code @transactional spring jdbctemplate code? @transactional(rollbackfor={dataaccessexception.class}) public void test(){ jdbctemplate.execute("insert test1 (id, nam) values (4, 'a')"); throw new dataaccessexception("error") { }; } here trying throw error, insert statement should rollback it's not happening . thanks edit-1 attaching code , doing in jdbcdaoimpl.java , mentioned problem comment above test() . app.java package com.cgiri.javabrains.spring4; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.applic...
Read more