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Merge Binary Search Trees (C++)
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/* | |
* Copyright (c) 2013 Remko Tronçon | |
* Licensed under the simplified BSD license. | |
*/ | |
#include <gmock/gmock.h> | |
#include <boost/coroutine/coroutine.hpp> | |
#include <functional> | |
using namespace testing; | |
using namespace std; | |
using namespace std::tr1::placeholders; | |
using boost::coroutines::coroutine; | |
/** | |
* Tree datatype | |
*/ | |
template<typename T> struct Node { | |
Node(T value, shared_ptr<Node<T>> left, shared_ptr<Node<T>> right) : | |
value(value), left(left), right(right) { | |
} | |
T value; | |
shared_ptr<Node<T>> left; | |
shared_ptr<Node<T>> right; | |
}; | |
template<typename T> shared_ptr<Node<T>> node( | |
T value, | |
shared_ptr<Node<T>> left = shared_ptr<Node<T>>(), | |
shared_ptr<Node<T>> right = shared_ptr<Node<T>>()) { | |
return make_shared<Node<T>>(value, left, right); | |
} | |
/** | |
* Walk a tree in in-order, and call 'c' for each value. | |
*/ | |
template<typename T> | |
void walk(shared_ptr<Node<T>> node, typename coroutine<int()>::caller_type& c) { | |
if (node) { | |
walk(node->left, c); | |
c(node->value); | |
walk(node->right, c); | |
} | |
} | |
/** | |
* Example trees | |
*/ | |
auto tree1 = | |
node(8, | |
node(4, node(2), node(5)), | |
node(12, node(10), node(16))); | |
auto tree2 = | |
node(9, | |
node(5, node(3), node(6)), | |
node(13, node(11), node(17))); | |
/** | |
* Collect the merged values into a vector. | |
*/ | |
TEST(MergeBST, CollectValues) { | |
coroutine<int()> flatTree1(bind(walk<int>, tree1, _1)); | |
coroutine<int()> flatTree2(bind(walk<int>, tree2, _1)); | |
vector<int> mergedTrees; | |
merge( | |
boost::begin(flatTree1), boost::end(flatTree1), | |
boost::begin(flatTree2), boost::end(flatTree2), | |
back_inserter(mergedTrees)); | |
const int expectedElements[] = { 2, 3, 4, 5, 5, 6, 8, 9, 10, 11, 12, 13, 16, 17 }; | |
ASSERT_THAT(mergedTrees, ElementsAreArray(expectedElements)); | |
} | |
/** | |
* Print the merged values directly to stdout. | |
*/ | |
TEST(MergeBST, PrintValues) { | |
coroutine<int()> flatTree1(bind(walk<int>, tree1, _1)); | |
coroutine<int()> flatTree2(bind(walk<int>, tree2, _1)); | |
merge( | |
boost::begin(flatTree1), boost::end(flatTree1), | |
boost::begin(flatTree2), boost::end(flatTree2), | |
ostream_iterator<int>(cout, " ")); | |
} | |
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