数据结结构学习 ---赫夫曼树

------ 赫夫曼树和赫夫曼编码的存储表示------

 

typedef struct {

	unsigned int weight;

	unsigned int parent,lchild,rchild;

}HTNode,*HuffmanTree;

typedef char ** HuffmanCode;



void HuffmanCoding(HuffmanTree& HT,HuffmanCode & HC,int *w,int n)  {



	if (n < 1) return;\

	int	m = 2* n + 1;

	HT = (HuffmanTree) malloc (m+1)* sizeof(HTNode); //0 号单元未用

	for ( HuffmanTree p = HT; i=1; i<=n; ++i; ++p; ++w)  

		*p = {*w,0,0,0,0};

	for(; i<=m; ++i; ++p)

		*p = {0,0,0,0};



	for(i = n+1; i<=m; i++) {  //建立HuffmanTree



		Select(HT,i-1,s1,s2);

		HT[s1].parent = i; 

		HT[s2].parent = i; 

		HT[i].lchild = s1;

		HT[i].rchild = s2;

		HT[i].weight = HT[s1].weight + HT[s2].weight;

	}



	HC = (HuffmanCode)malloc((n+1)* sizeof(char*));

	cd = (char*) malloc(n* sizeof(char));

	cd [n-1] = "\0";

	for ( i=1; i<=n; i++) {

		int start = n-1;

		for ( c=i, f = HT[i].parent; f!=0; c=f; f = HT[f].parent )

			if( HT[f].lchild == c )  cd [--start] = "0";

			else cd [--start] = "1";

		HC[i] = (char*) malloc ( (n-start)* sizeof(char)); 

		strcyp(HC[i],&cd[start]);

	}

	free(cd);



}

 

------ 无栈非递归遍历赫夫曼树，求赫夫曼编码------

 

HC = (HuffmanCode) malloc ( (n+1) *　sizeof(char*)); 

int p = m, cdlen = 0;



for ( int i=1; i<=m; ++i)  HT[i].weight = 0;



while(p) {



    if ( HT[p].weight == 0 ) {



        HT[p].weight = 1; 

        if ( HT[p].lchild != 0) {

            p = HT[p].lchild; 

            cd[cdlen++] = "0";

        }else if ( HT[p].lchild == 0) {



            HC[p] = (char*) malloc ((cdlen+1) * sizeof(char));

            cd[cdlen] = "\0"; 

            strcpy(HC[p],cd);

        }

    }else if ( HP[p].weight == 1) {



        HT[p].weight = 2;

        if ( HT[p].rchild != 0) {

            p = HT[p].rchild;

            cd [cdlen++] = "1";

        }else {

            HT[p].weight = 0; p = HT[p].parent; --cdlen;

        }

    }    

}