C++ 二叉搜索树最佳拟合Alg.:输出不正确
免责声明:这是学校作业 嘿,大家好。我花了两周的时间在这个垃圾箱打包程序上,我还有最后一个障碍要克服:我的二叉搜索树的find函数给了我不正确的结果 BinarySearchTree.cppC++ 二叉搜索树最佳拟合Alg.:输出不正确,c++,find,binary-search-tree,bin-packing,best-fit,C++,Find,Binary Search Tree,Bin Packing,Best Fit,免责声明:这是学校作业 嘿,大家好。我花了两周的时间在这个垃圾箱打包程序上,我还有最后一个障碍要克服:我的二叉搜索树的find函数给了我不正确的结果 BinarySearchTree.cpp #include "BinarySearchTree.h" void BinarySearchTree::insert(int capacity, int binNumber) { // Insert the Pair into the tree. Overwrite existing /
#include "BinarySearchTree.h"
void BinarySearchTree::insert(int capacity, int binNumber)
{
// Insert the Pair into the tree. Overwrite existing
// pair, if any, with same key.
// find place to insert
BinaryTreeNode *p = root,
*pp = NULL;
while (p != NULL)
{// examine p->capacity
pp = p;
// move p to a child
if (capacity <= p->capacity)
p = p->leftChild;
else
p = p->rightChild;
}
// get a node for the Pair and attach to pp
BinaryTreeNode *newNode = new BinaryTreeNode (capacity, binNumber);
if (root != NULL) // the tree is not empty
if (capacity <= pp->capacity)
pp->leftChild = newNode;
else
pp->rightChild = newNode;
else
root = newNode; // insertion into empty tree
treeSize++;
}
void BinarySearchTree::erase(BinaryTreeNode *n)
{
// Delete the pair, if any, whose key equals n.
// search for node with key theKey
BinaryTreeNode *p = root,
*pp = NULL;
while (p != NULL && p->capacity != n->capacity)
{// move to a child of p
pp = p;
if (n->capacity < p->capacity)
p = p->leftChild;
else
p = p->rightChild;
}
if (p == NULL)
return; // no pair with key theKey
// restructure tree
// handle case when p has two children
if (p->leftChild != NULL && p->rightChild != NULL)
{// two children
// convert to zero or one child case
// find largest element in left subtree of p
BinaryTreeNode *s = p->leftChild,
*ps = p; // parent of s
while (s->rightChild != NULL)
{// move to larger element
ps = s;
s = s->rightChild;
}
// move largest from s to p, can't do a simple move
// p->capacity= s->capacity as key is const
BinaryTreeNode *q = new BinaryTreeNode (s->capacity,s->binNumber, p->leftChild, p->rightChild, p->parent);
if (pp == NULL)
root = q;
else if (p == pp->leftChild)
pp->leftChild = q;
else
pp->rightChild = q;
if (ps == p) pp = q;
else pp = ps;
delete p;
p = s;
}
// p has at most one child
// save child pointer in c
BinaryTreeNode *c;
if (p->leftChild != NULL)
c = p->leftChild;
else
c = p->rightChild;
// delete p
if (p == root)
root = c;
else
{// is p left or right child of pp?
if (p == pp->leftChild)
pp->leftChild = c;
else pp->rightChild = c;
}
treeSize--;
delete p;
}
BinaryTreeNode* BinarySearchTree::find(const int objectSize) const
{
// Return pointer to pair with smallest key >= objectSize.
// Return NULL if no element has key >= objectSize.
BinaryTreeNode *currentNode = root,
*bestElement = NULL; // element with smallest key
// >= theKey found so far
// search the tree
while (currentNode != NULL) {
// is currentNode->capacity a candidate?
if (currentNode->capacity >= objectSize)
{
// smaller keys in left subtree only
bestElement = currentNode;
currentNode = currentNode->leftChild;
}
else if (currentNode->capacity < objectSize)
{
// no, currentNode->capacity is too small
// try right subtree
currentNode = currentNode->rightChild;
}
}
return bestElement;
}
void BinPacking::bestFitPack(int *objectSize, int numberOfObjects, int binCapacity)
{// Output best-fit packing into bins of size binCapacity.
// objectSize[1:numberOfObjects] are the object sizes.
int n = numberOfObjects;
int binsUsed = 0;
BinarySearchTree theTree; // tree of bin capacities
BinaryTreeNode theBin;
// pack objects one by one
for (int i = 1; i <= n; i++)
{// pack object i
// find best bin
BinaryTreeNode *bestBin = theTree.find(objectSize[i]);
if (bestBin == NULL)
{// no bin large enough, start a new bin
theBin.capacity = binCapacity;
theBin.binNumber = ++binsUsed;
}
else
{// remove best bin from theTree
theBin = *bestBin;
theTree.erase(bestBin);
}
cout << "Pack object " << i << " in bin " << theBin.binNumber << endl;
// insert bin in tree unless bin is full
theBin.capacity -= objectSize[i];
if (theBin.capacity > 0)
theTree.insert(theBin.capacity, theBin.binNumber);
}
}
BinPacking.cpp
#include "BinarySearchTree.h"
void BinarySearchTree::insert(int capacity, int binNumber)
{
// Insert the Pair into the tree. Overwrite existing
// pair, if any, with same key.
// find place to insert
BinaryTreeNode *p = root,
*pp = NULL;
while (p != NULL)
{// examine p->capacity
pp = p;
// move p to a child
if (capacity <= p->capacity)
p = p->leftChild;
else
p = p->rightChild;
}
// get a node for the Pair and attach to pp
BinaryTreeNode *newNode = new BinaryTreeNode (capacity, binNumber);
if (root != NULL) // the tree is not empty
if (capacity <= pp->capacity)
pp->leftChild = newNode;
else
pp->rightChild = newNode;
else
root = newNode; // insertion into empty tree
treeSize++;
}
void BinarySearchTree::erase(BinaryTreeNode *n)
{
// Delete the pair, if any, whose key equals n.
// search for node with key theKey
BinaryTreeNode *p = root,
*pp = NULL;
while (p != NULL && p->capacity != n->capacity)
{// move to a child of p
pp = p;
if (n->capacity < p->capacity)
p = p->leftChild;
else
p = p->rightChild;
}
if (p == NULL)
return; // no pair with key theKey
// restructure tree
// handle case when p has two children
if (p->leftChild != NULL && p->rightChild != NULL)
{// two children
// convert to zero or one child case
// find largest element in left subtree of p
BinaryTreeNode *s = p->leftChild,
*ps = p; // parent of s
while (s->rightChild != NULL)
{// move to larger element
ps = s;
s = s->rightChild;
}
// move largest from s to p, can't do a simple move
// p->capacity= s->capacity as key is const
BinaryTreeNode *q = new BinaryTreeNode (s->capacity,s->binNumber, p->leftChild, p->rightChild, p->parent);
if (pp == NULL)
root = q;
else if (p == pp->leftChild)
pp->leftChild = q;
else
pp->rightChild = q;
if (ps == p) pp = q;
else pp = ps;
delete p;
p = s;
}
// p has at most one child
// save child pointer in c
BinaryTreeNode *c;
if (p->leftChild != NULL)
c = p->leftChild;
else
c = p->rightChild;
// delete p
if (p == root)
root = c;
else
{// is p left or right child of pp?
if (p == pp->leftChild)
pp->leftChild = c;
else pp->rightChild = c;
}
treeSize--;
delete p;
}
BinaryTreeNode* BinarySearchTree::find(const int objectSize) const
{
// Return pointer to pair with smallest key >= objectSize.
// Return NULL if no element has key >= objectSize.
BinaryTreeNode *currentNode = root,
*bestElement = NULL; // element with smallest key
// >= theKey found so far
// search the tree
while (currentNode != NULL) {
// is currentNode->capacity a candidate?
if (currentNode->capacity >= objectSize)
{
// smaller keys in left subtree only
bestElement = currentNode;
currentNode = currentNode->leftChild;
}
else if (currentNode->capacity < objectSize)
{
// no, currentNode->capacity is too small
// try right subtree
currentNode = currentNode->rightChild;
}
}
return bestElement;
}
void BinPacking::bestFitPack(int *objectSize, int numberOfObjects, int binCapacity)
{// Output best-fit packing into bins of size binCapacity.
// objectSize[1:numberOfObjects] are the object sizes.
int n = numberOfObjects;
int binsUsed = 0;
BinarySearchTree theTree; // tree of bin capacities
BinaryTreeNode theBin;
// pack objects one by one
for (int i = 1; i <= n; i++)
{// pack object i
// find best bin
BinaryTreeNode *bestBin = theTree.find(objectSize[i]);
if (bestBin == NULL)
{// no bin large enough, start a new bin
theBin.capacity = binCapacity;
theBin.binNumber = ++binsUsed;
}
else
{// remove best bin from theTree
theBin = *bestBin;
theTree.erase(bestBin);
}
cout << "Pack object " << i << " in bin " << theBin.binNumber << endl;
// insert bin in tree unless bin is full
theBin.capacity -= objectSize[i];
if (theBin.capacity > 0)
theTree.insert(theBin.capacity, theBin.binNumber);
}
}
预期产出
Pack object 1 in bin 1
Pack object 2 in bin 2
Pack object 3 in bin 3
Pack object 4 in bin 2
Pack object 5 in bin 3
Pack object 6 in bin 1
Pack object 7 in bin 4
Pack object 8 in bin 5
Pack object 9 in bin 4
Pack object 10 in bin 6
Pack object 11 in bin 7
Pack object 12 in bin 1
Pack object 1 in bin 1
Pack object 2 in bin 2
Pack object 3 in bin 3
Pack object 4 in bin 3
Pack object 5 in bin 3
Pack object 6 in bin 1
Pack object 7 in bin 4
Pack object 8 in bin 5
Pack object 9 in bin 4
Pack object 10 in bin 6
Pack object 11 in bin 7
Pack object 12 in bin 6
电流输出
Pack object 1 in bin 1
Pack object 2 in bin 2
Pack object 3 in bin 3
Pack object 4 in bin 2
Pack object 5 in bin 3
Pack object 6 in bin 1
Pack object 7 in bin 4
Pack object 8 in bin 5
Pack object 9 in bin 4
Pack object 10 in bin 6
Pack object 11 in bin 7
Pack object 12 in bin 1
Pack object 1 in bin 1
Pack object 2 in bin 2
Pack object 3 in bin 3
Pack object 4 in bin 3
Pack object 5 in bin 3
Pack object 6 in bin 1
Pack object 7 in bin 4
Pack object 8 in bin 5
Pack object 9 in bin 4
Pack object 10 in bin 6
Pack object 11 in bin 7
Pack object 12 in bin 6
我知道我马上就要完成这项任务了。我知道问题出在哪里,但我一直没能解决。请帮我一下好吗?错误出现在您的代码中,
erase()
中:
无论如何,擦除不在树中的节点是非法的,因此唯一有效的终止条件是找到该节点
找到要擦除的节点后,以下伪代码应正确旋转树:
if (pp->capacity >= n->capacity)
parent_to_me = &pp->leftChild;
else
parent_to_me = &pp->rightChild;
if (!node->leftChild && !node->rightChild)
{
// point to nothing
*parent_to_me = NULL;
} else if (node->leftChild)
{
if (!node->rightChild)
{
// left child, but no right child:
// promote left child to self
*parent_to_me = node->leftChild;
} else
{
// left and right children: Make right child the
// right child of the right-most left sub-child.
// Replace myself with left child.
Node *rmlsc = node->leftChild;
while (rmlsc->rightChild)
rmlsc = rmlsc->rightChild;
rmlsc->rightChild = node->rightChild;
*parent_to_me = node->leftChild;
}
} else
*parent_to_me = node->rightChild;
你没有建立“最佳元素”的逻辑。只有在完全匹配时才返回非空节点。当对象大小与初始箱子大小不匹配时,代码如何工作?当你决定把东西装进垃圾箱时,你会怎么做?它的大小改变了,所以它在树中的位置也需要改变。实际上,我刚刚意识到我有一个旧版本的代码。我刚修改过。输出也已更新。好的,您的搜索现在看起来很好。但是,一旦你把一个对象分配到一个箱子里,你会怎么做呢?箱子的剩余容量将减少,因此箱子在搜索树中的位置需要更改。您还没有向我们展示在
find()
节点之后要做什么。好的,我刚刚添加了我的最佳拟合算法,它显示了在找到节点后会发生什么。这看起来很有希望。擦除
做什么,以及插入
做什么?前3个对象已打包,但它显示“分段错误(内核转储)”。好的,现在我需要更仔细地查看其余的擦除代码。我看到你在那里分配了一个新元素,这是不必要的。它总是一个“旋转”。你必须找到合适的偏心点才能旋转到被删除元素的位置。好的,我将在上面放一些伪代码,说明当你删除一个键时应该如何处理“旋转”。这是伪代码,你必须把它重新编译成你自己的程序。我将使用这个伪代码,希望这件事能得到解决。我非常感谢你在这方面的帮助,Joe Z。希望伪代码有意义。你应该能够画出图表,看看它是如何工作的。