#define MAXVALUE 100000
using namespace std;
const int n = 4 ; // 叶子节点个数
// 构造哈夫曼树结点
typedef struct {
int weight; // 权值
int parent; // 父节点
int lchild; // 左子树
int rchild; // 右子树
}HNodeType;
HNodeType HFMTree[ 2 * n - 1 ]; // 结点数
// 构造哈夫曼编码数组
typedef struct {
int bit[n];
int start;
}HCodeType;
HCodeType HFMCode[n];
// 创建哈夫曼树
void createHFMTree(HNodeType HFMTree[], int n){
int m1,x1,m2,x2;
int i,j;
// 初始化
for (i = 0 ;i < 2 * n - 1 ;i ++ ){
HFMTree[i].weight = 0 ;
HFMTree[i].parent =- 1 ;
HFMTree[i].lchild =- 1 ;
HFMTree[i].rchild =- 1 ;
}
cout << " 请输入结点权值： " << endl;
for (i = 0 ;i < n;i ++ ){
cin >> HFMTree[i].weight;
}
for (i = 0 ;i < n - 1 ;i ++ ){
x1 = x2 = MAXVALUE;
m1 = m2 = 0 ;
for (j = 0 ;j < n + i;j ++ ){
if (HFMTree[j].parent ==- 1 && HFMTree[j].weight < x1){
x2 = x1;
m2 = m1;
x1 = HFMTree[j].weight;
m1 = j;
}
else if (HFMTree[j].parent ==- 1 && HFMTree[j].weight < x2){
x2 = HFMTree[j].weight;
m2 = j;
}
}
HFMTree[m1].parent = n + i;HFMTree[m2].parent = n + i;
HFMTree[n + i].weight = HFMTree[m1].weight + HFMTree[m2].weight;
HFMTree[n + i].lchild = m1;
HFMTree[n + i].rchild = m2;
}
}
// 转化编码
void createHFMCode(HNodeType HFMTree[],HCodeType HFMCode[]){
HCodeType cd;
int i,j,c,p;
for (i = 0 ;i < n;i ++ ){
cd.start = n - 1 ;
c = i;
p = HFMTree[c].parent;
while (p !=- 1 )
{
if (HFMTree[p].lchild == c)cd.bit[cd.start] = 0 ;
else cd.bit[cd.start] = 1 ;
cd.start -- ;
c = p;
p = HFMTree[c].parent;
}
for (j = cd.start + 1 ;j < n;j ++ )
HFMCode[i].bit[j] = cd.bit[j];
HFMCode[i].start = cd.start + 1 ;
}
}
// 主函数
int main()
{
int i,j;
// 创建树
createHFMTree(HFMTree,n);
// 转码
createHFMCode(HFMTree,HFMCode);
cout << endl;
for (i = 0 ;i < n;i ++ )
{
for (j = HFMCode[i].start;j <= n - 1 ;j ++ )
{
cout << HFMCode[i].bit[j];
}
cout << endl;
}
return 0 ;
}
这个是雏形，下面我们要实现的功能是，输入一个含有N位A,B,C,D四种字母的字符串。
然后转换成只含有0，1的代码串。之所以要使用哈夫曼树是因为哈夫曼树是最优树。根据权值来实现最短编码。
下面是实现自动转码的程序：
#define MAXVALUE 100000
using namespace std;
const int n = 4 ; // 叶子节点个数
string l;
int size;
// 构造哈夫曼树结点
typedef struct {
int weight; // 权值
int parent; // 父节点
int lchild; // 左子树
int rchild; // 右子树
}HNodeType;
HNodeType HFMTree[ 2 * n - 1 ]; // 结点数
// 构造哈夫曼编码数组
typedef struct {
int bit[n];
int start;
}HCodeType;
HCodeType HFMCode[n];
// 创建哈夫曼树
void createHFMTree(HNodeType HFMTree[], int n){
int m1,x1,m2,x2;
int i,j;
// 初始化
for (i = 0 ;i < 2 * n - 1 ;i ++ ){
HFMTree[i].weight = 0 ;
HFMTree[i].parent =- 1 ;
HFMTree[i].lchild =- 1 ;
HFMTree[i].rchild =- 1 ;
}
cout << " *******************哈夫曼树字符串最优转码程序*********************** " << endl;
cout << " 请输入一个字符串：(只含有A，B，C，D四种字符,输入回车结束) " << endl;
cin >> l;
std:: string str(l);
size = str.size();
for ( int i = 0 ;i < size; ++ i){
if (str.at(i) == ' A ' )HFMTree[ 0 ].weight ++ ;
else if (str.at(i) == ' B ' )HFMTree[ 1 ].weight ++ ;
else if (str.at(i) == ' C ' )HFMTree[ 2 ].weight ++ ;
else if (str.at(i) == ' D ' )HFMTree[ 3 ].weight ++ ;
else {
cout << " 输入有误! " << endl;
break ;
}
}
for (i = 0 ;i < n - 1 ;i ++ ){
x1 = x2 = MAXVALUE;
m1 = m2 = 0 ;
for (j = 0 ;j < n + i;j ++ ){
if (HFMTree[j].parent ==- 1 && HFMTree[j].weight < x1){
x2 = x1;
m2 = m1;
x1 = HFMTree[j].weight;
m1 = j;
}
else if (HFMTree[j].parent ==- 1 && HFMTree[j].weight < x2){
x2 = HFMTree[j].weight;
m2 = j;
}
}
HFMTree[m1].parent = n + i;HFMTree[m2].parent = n + i;
HFMTree[n + i].weight = HFMTree[m1].weight + HFMTree[m2].weight;
HFMTree[n + i].lchild = m1;
HFMTree[n + i].rchild = m2;
}
}
// 转化编码
void createHFMCode(HNodeType HFMTree[],HCodeType HFMCode[]){
HCodeType cd;
int i,j,c,p;
for (i = 0 ;i < n;i ++ ){
cd.start = n - 1 ;
c = i;
p = HFMTree[c].parent;
while (p !=- 1 )
{
if (HFMTree[p].lchild == c)cd.bit[cd.start] = 0 ;
else cd.bit[cd.start] = 1 ;
cd.start -- ;
c = p;
p = HFMTree[c].parent;
}
for (j = cd.start + 1 ;j < n;j ++ )
HFMCode[i].bit[j] = cd.bit[j];
HFMCode[i].start = cd.start + 1 ;
}
}
// 主函数
int main()
{
int i,j;
// 创建树
createHFMTree(HFMTree,n);
// 转码
createHFMCode(HFMTree,HFMCode);
cout << endl;
int k = 65 ;
for (i = 0 ;i < n;i ++ )
{
cout << ( char )k << " 的编码： " ;
for (j = HFMCode[i].start;j <= n - 1 ;j ++ )
{
cout << HFMCode[i].bit[j];
}
k ++ ;
cout << endl;
}
cout << " 转码后的字符串为： " << endl;
std:: string str(l);
size = str.size();
for ( int i = 0 ;i < size; ++ i){
if (str.at(i) == ' A ' ){
for (j = HFMCode[ 0 ].start;j <= n - 1 ;j ++ )
cout << HFMCode[ 0 ].bit[j];
}
else if (str.at(i) == ' B ' ){
for (j = HFMCode[ 1 ].start;j <= n - 1 ;j ++ )
cout << HFMCode[ 1 ].bit[j];
}
else if (str.at(i) == ' C ' ){
for (j = HFMCode[ 2 ].start;j <= n - 1 ;j ++ )
cout << HFMCode[ 2 ].bit[j];
}
else if (str.at(i) == ' D ' ){
for (j = HFMCode[ 3 ].start;j <= n - 1 ;j ++ )
cout << HFMCode[ 3 ].bit[j];
}
else {
cout << " 输入有误! " << endl;
break ;
}
}
return 0 ;
}
程序本机测试通过，可以放心运行！
本文转自施杨博客园博客，原文链接：http://www.cnblogs.com/shiyangxt/archive/2008/12/05/1348174.html，如需转载请自行联系原作者
