Huffman

一脸懵逼， 喝了女票的咖啡， 睡不着提不起劲， 不能再拖了， 得马上攻下， code是copy别人的（哭泣脸）， 需谨记！！！

题目链接：https://pta.patest.cn/pta/test/1342/exam/4/question/21733

代码来源：http://blog.csdn.net/xijujie/article/details/53046057

/**    Donald    2016.11.6*///05-树10 Huffman Codes   (30分)/**    1.计算最优编码长度    2.对每位学生的提交，检查        * 长度是否正确 Len = 总（i - (x-1)）strlen(code[i]) * f[i];            *注意：Code[i]的最大查毒为N - 1        * 建树过程中检查是否满足前缀码要求*///Huffman编码不唯一//Huffman编码是最优编码，但最优编码不一定是Huffman编码//需要满足的条件//1最优：wpl最小  建立Huffman树计算最小wpl判断学生的提交是否正确//2无歧义：前缀码  建树过程中检查是否满足前缀码要求#include <stdio.h>#include <stdlib.h>#include <ctype.h>#include <string.h>#define MinData -1#define N 64typedef struct HuTreeNode *HuffmanTree;typedef struct HNode *Heap;typedef struct BiTreeNode *BinTree;struct HuTreeNode {    int Weight;    HuffmanTree Left, Right;};struct HNode {    HuffmanTree* Data;    int Size;};struct BiTreeNode {    int flag;    BinTree Left, Right;};HuffmanTree BuiltHuffman(Heap H);HuffmanTree DeleteMinHeap(Heap H);void InsertMinHeap(Heap H, HuffmanTree HT);int Wpl(HuffmanTree HT, int depth);void CheckPrefixcode(BinTree BT, char *str, int *flag);BinTree Delete(BinTree BT);int main(void) {    int i, n, m, wpl, flag, frequency[N], w;    char ch, str[N];    Heap H = (Heap)malloc(sizeof(struct HNode));    HuffmanTree HT;    BinTree BT;    scanf("%d\n", &n);    H->Data = (HuffmanTree*)malloc((n + 1)*sizeof(HuffmanTree));    H->Data[0] = (HuffmanTree)malloc(sizeof(struct HuTreeNode));    H->Data[0]->Weight = MinData;    H->Size = 0;    for (i = 1;i <= n;i++) {        ch = getchar();        if(!isalpha(ch))            ch = getchar();        scanf(" %d", &frequency[i]);        HT = (HuffmanTree)malloc(sizeof(struct HuTreeNode));        HT->Weight = frequency[i];        HT->Left = HT->Right = NULL;        InsertMinHeap(H, HT);    }    HT = BuiltHuffman(H);    w = Wpl(HT, 0);    ch = getchar();    scanf("%d\n", &m);    while (m--) {        wpl = 0;        flag = 0;        BT = (BinTree)malloc(sizeof(struct BiTreeNode));        BT->flag = 0;        BT->Left = BT->Right = NULL;        for (i = 0;i < n;i++) {            scanf("%c %s\n", &ch, str);            wpl += strlen(str) * frequency[i+1];            if(!flag)                CheckPrefixcode(BT, str, &flag);        }        if (flag || wpl > w)            printf("No\n");        else printf("Yes\n");        BT = Delete(BT);    }}//建立Huffman树HuffmanTree BuiltHuffman(Heap H) {    int i, k = H->Size - 1;    HuffmanTree HT;    for (i = 0;i < k;i++) {        HT = (HuffmanTree)malloc(sizeof(struct HuTreeNode));        HT->Left = DeleteMinHeap(H);        HT->Right = DeleteMinHeap(H);        HT->Weight = HT->Left->Weight + HT->Right->Weight;        InsertMinHeap(H, HT);    }    return DeleteMinHeap(H);}//从最小堆中删除元素HuffmanTree DeleteMinHeap(Heap H) {    int i, child;    HuffmanTree MinItem, LastItem;    MinItem = H->Data[1];    LastItem = H->Data[H->Size--];    for (i = 1;i * 2 <= H->Size;i = child) {        child = i * 2;        if (child < H->Size && H->Data[child + 1]->Weight < H->Data[child]->Weight)            child++;        if(LastItem->Weight > H->Data[child]->Weight)            H->Data[i] = H->Data[child];        else break;    }    H->Data[i] = LastItem;    return MinItem;}//向最小堆中插入元素void InsertMinHeap(Heap H, HuffmanTree HT) {    int i;    for (i = ++H->Size; H->Data[i / 2]->Weight > HT->Weight; i /= 2)        H->Data[i] = H->Data[i / 2];    H->Data[i] = HT;}//计算最优编码长度int Wpl(HuffmanTree HT, int depth) {    if (!HT->Left && !HT->Right)        return depth*HT->Weight;    else        return Wpl(HT->Left, depth + 1) + Wpl(HT->Right, depth + 1);}//检查是否为前缀码void CheckPrefixcode(BinTree BT, char *str, int *flag) {    size_t i;    for (i = 0;i < strlen(str);i++) {        if (BT->flag) //非叶子节点存在元素        {            *flag = 1;            return;        }        if (str[i] == '0') {            if (!BT->Left) {                BinTree T = (BinTree)malloc(sizeof(struct BiTreeNode));                T->flag = 0;                T->Left = T->Right = NULL;                BT->Left = T;            }            BT = BT->Left;        }        else {            if (!BT->Right) {                BinTree T = (BinTree)malloc(sizeof(struct BiTreeNode));                T->flag = 0;                T->Left = T->Right = NULL;                BT->Right = T;            }            BT = BT->Right;        }    }    //该节点将写入元素，如果已经存在元素（重合）或者非叶节点（存在子树），则不是前缀码    if (BT->flag || BT->Left || BT->Right) {        *flag = 1;        return;    }    BT->flag = 1;}//删除树BinTree Delete(BinTree BT) {    if (!BT->Left && !BT->Right) {        free(BT);        BT = NULL;    }    else {        if (BT->Left)            BT->Left = Delete(BT->Left);        if (BT->Right)            BT->Right = Delete(BT->Right);    }    return BT;}