// The main function that builds Huffman tree
struct MinHeapNode* buildHuffmanTree(char data[], int freq[], int size)
{
struct MinHeapNode *left, *right, *top;
// Step 1: Create a min heap of capacity equal to size. Initially, there are
// modes equal to size.
struct MinHeap* minHeap = createAndBuildMinHeap(data, freq, size);
// Iterate while size of heap doesn't become 1
while (!isSizeOne(minHeap))
{
// Step 2: Extract the two minimum freq items from min heap
left = extractMin(minHeap);
right = extractMin(minHeap);
// Step 3: Create a new internal node with frequency equal to the
// sum of the two nodes frequencies. Make the two extracted node as
// left and right children of this new node. Add this node to the min heap
// '$' is a special value for internal nodes, not used
top = newNode('$', left->freq + right->freq);
top->left = left;
top->right = right;
insertMinHeap(minHeap, top);
}
// Step 4: The remaining node is the root node and the tree is complete.
return extractMin(minHeap);
}
MinHeapNode* buildHuffmanTree (char data[], int freq[], int size)
{
MinHeapNode* left; MinHeapNode* right; MinHeapNode* top;
MinHeap* minHeap = createAndBuildMinHeap(data,freq,size);
while (!isSizeOne(minHeap))
{
left = extractMin(minHeap);
right = extractMin(minHeap);
top = newNode('$', left->freq + right->freq);
top->left = left;
top->right = right;
insertMinHeap(minHeap,top);
}
return extractMin(minHeap);
}
// The main function that builds Huffman tree
struct MinHeapNode* buildHuffmanTree(uint16 freq[])
{
struct MinHeapNode *left, *right, *top, *ret_node;
// Step 1: Create a min heap of capacity equal to size. Initially, there are
// modes equal to size.
struct MinHeap* minHeap = createAndBuildMinHeap(freq, HUFFMAN_STEPS);
if (minHeap == NULL) {
hError |= (1 << 5);
return NULL;
}
// Iterate while size of heap doesn't become 1
while (!isSizeOne(minHeap))
{
// Step 2: Extract the two minimum freq items from min heap
left = extractMin(minHeap);
right = extractMin(minHeap);
// Step 3: Create a new internal node with frequency equal to the
// sum of the two nodes frequencies. Make the two extracted node as
// left and right children of this new node. Add this node to the min heap
// '$' is a special value for internal nodes, not used
top = newNode('$', left->freq + right->freq);
if (top == NULL) {
hError |= (1 << 6);
return NULL;
}
top->left = left;
top->right = right;
insertMinHeap(minHeap, top);
}
// Step 4: The remaining node is the root node and the tree is complete.
ret_node = extractMin(minHeap);
osal_mem_free(minHeap);
return ret_node;
}
