Huffman编码代码

Huffman编码

Huffman编码是一种可变字长编码，利用字频来作为结点的权重，代码如下，测试使用的是26个字母，频率使用的是Prime.

#include 
#include 
#include 
#include 
using namespace std;
string road[26];
int key[26] = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101};

struct Node
{
    int value = -1;
    int lchild = -1;
    int rchild = -1;
    int parent = -1;
};
int Select(Node tree[], int n)
{
    int min, i = 0;
    for(; i < n; i++)
        if(tree[i].value != -1 && tree[i].parent == -1)
        {
            min = i;
            break;
        }
    for(; i < n; i++)
        if(tree[i].value != -1 && tree[i].parent == -1 && tree[i].value <= tree[min].value)
            min = i;
    return min;
}
string search(Node tree[], int i, string s, int num)
{
    if(tree[i].parent == -1)
        return (tree[i].lchild == num) ? "0" + s : "1" + s;
    if(tree[i].lchild == num)
        return search(tree, tree[i].parent, "0" + s, i);
    else
        return search(tree, tree[i].parent, "1" + s, i);

}
void Huffman(Node tree[], int n)
{
    for(int i = 0; i < n; i++)
        tree[i].value = key[i];
    int m = 2 * n - 1;
    for(int i = n; i < m; i++)
    {
        int lmin, rmin;
        //查找权值最小的两个根节点保存在lmin和rmin中
        lmin = Select(tree, m);
        tree[lmin].parent = i;
        rmin = Select(tree, m);
        tree[rmin].parent = i;
        tree[i].value = tree[lmin].value + tree[rmin].value;
        tree[i].lchild = lmin;
        tree[i].rchild = rmin;
    }
}
int main()
{
    int n = 26;
    int m = n * 2 - 1;
    Node *tree = new Node[m];
    Huffman(tree, n);
    printf("    序号   权值   双亲   左孩   右孩\n");
    for(int i = 0; i < n; i++)
        printf("%c%7d%7d%7d%7d%7d\n", ('a' + i), i, tree[i].value, tree[i].parent, tree[i].lchild, tree[i].rchild);
    for(int i = n; i < m; i++)
        printf(" %7d%7d%7d%7d%7d\n", i, tree[i].value, tree[i].parent, tree[i].lchild, tree[i].rchild);
    printf("   编码\n");
    for(int i = 0; i < n; i++)
    {
        road[i] = search(tree, tree[i].parent, "", i);
        printf("%c  ", ('a' + i));
        cout << road[i] << endl;
    }
    delete[] tree;
    system("pause");
    return 0;
}