哈夫曼树(最优二叉树)与哈夫曼编码

#ifndef __HUFFMANNODE_H__
#define __HUFFMANNODE_H__
class huffmanNode
{
public:
  int weight;
  int lchild, rchild, parent;
};
#endif

#include <iostream>
#include "huffmanNode.h"
using namespace std;
void selectMinWeight(huffmanNode *_huffmanTree, int _num, int &_minIndex1, int &_minIndex2)
{
  int i = 0, minWeight = 0;
  for (i = 0; i < _num; i++)
  if (_huffmanTree[i].parent == -1)
  {
    minWeight = i;
    break;
  }
  for (i = 0; i < _num; i++)
  if (_huffmanTree[i].parent == -1)
    if (_huffmanTree[i].weight < _huffmanTree[minWeight].weight)
    minWeight = i;
  _minIndex1 = minWeight;
  for (i = 0; i < _num; i++)
  if (_huffmanTree[i].parent == -1 && i != _minIndex1)
  {
    minWeight = i;
    break;
  }
  for (i = 0; i < _num; i++)
  if (_huffmanTree[i].parent == -1 && i != _minIndex1)
    if (_huffmanTree[i].weight < _huffmanTree[minWeight].weight)
    minWeight = i;
  _minIndex2 = minWeight;
}
//构造哈夫曼树
void HuffmanTree(huffmanNode *_huffmanTree, int _weight[], int _num)
{
  int i = 0;
  int minIndex1 = -1, minIndex2 = -1;
  for (i = 0; i < 2 * _num - 1; i++)
  {
  _huffmanTree[i].parent = -1;
  _huffmanTree[i].lchild = -1;
  _huffmanTree[i].rchild = -1;
  }
  for (i = 0; i < _num; i++)
  _huffmanTree[i].weight = _weight[i];
  //合并节点，构建哈夫曼树
  for (i = _num; i < 2 * _num - 1; i++)
  {
  selectMinWeight(_huffmanTree, i, minIndex1, minIndex2);
  _huffmanTree[minIndex1].parent = i;
  _huffmanTree[minIndex2].parent = i;
  _huffmanTree[i].lchild = minIndex1;
  _huffmanTree[i].rchild = minIndex2;
  _huffmanTree[i].weight = _huffmanTree[minIndex1].weight + _huffmanTree[minIndex2].weight;
  cout << _huffmanTree[i].weight << "(" << _huffmanTree[minIndex1].weight << "," << _huffmanTree[minIndex2].weight << ")" << endl;
  }
}
//求哈夫曼树的哈夫曼编码
void HuffmanCode(huffmanNode *_huffmanTree, int _num)
{
  int parentIndex = -1, j = 0;
  vector<int> code;
  vector<int> nodeCode;
  for (int i = 0; i < _num; i++)
  {
  j = i;
  while(_huffmanTree[j].parent != -1)
  {
    parentIndex = _huffmanTree[j].parent;
    if (j == _huffmanTree[parentIndex].lchild)
    nodeCode.insert(nodeCode.begin(), 0);
    else
    nodeCode.insert(nodeCode.begin(), 1);
    j = parentIndex;
  }
  code.insert(code.end(), nodeCode.begin(), nodeCode.end());
  nodeCode.clear();
  }
  for (unsigned int i = 0; i < code.size(); i++)
  cout << code.at(i);
  cout << endl;
}
int main()
{
  huffmanNode huffmanTree[2 * 5 - 1];
  int weight[] = { 35, 25, 15, 15, 10 };
  HuffmanTree(huffmanTree, weight, sizeof(weight) / sizeof(4));
  HuffmanCode(huffmanTree, sizeof(weight) / sizeof(4));
  return 0;
}

5(2,3)
9(4,5)
14(5,9)

||
                    ||
                    \/
                   4(5)
                  /    \
                0(2)   3(3)       
                    ||
                    ||
                    \/
           4(5)           5(9)
          /    \         /    \
        0(2)   3(3)   1(4)    2(5)
                    ||
                    ||
                    \/
                  6(14)
                /       \
            4(5)         5(9)
           /   \        /    \
        0(2)   3(3)   1(4)    2(5)
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