PAT 05-tree 8 Huffman Codes, 05-huffman

PAT 05-tree 8 Huffman Codes, 05-huffman

With the current productivity, it is impossible to get a blog one day. This is a rare problem for me. I spent two days on PAT and I haven't passed the test point 1. Write it first. Record several difficult points: 1. I wanted to use a function to implement WPL, but I had no choice but to transmit string arrays. 2. The level is not enough, the questions are basically a variety of references. Of course, the courseware (Netease cloud class "data structure" (Chen Yue, He qinming) is the main method. However, I have been unable to determine the type of ElementType, and finally referred to the friends of the rough brother (http://www.cnblogs.com/liangchao/p/4286598.html#3158189) blog; 3, on how to determine whether the method is a prefix code, I am using the most violent one-to-one comparison. I don't know how to achieve it better. Okay. The specific questions and code implementation before test point 1 are as follows:

  1 /*  2     Name:   3     Copyright:   4     Author:   5     Date: 07/04/15 11:05  6     Description:   7 In 1953, David A. Huffman published his paper "A Method for the Construction of Minimum-Redundancy Codes", and hence printed his name in the history of computer science. As a professor who gives the final exam problem on Huffman codes, I am encountering a big problem: the Huffman codes are NOT unique. For example, given a string "aaaxuaxz", we can observe that the frequencies of the characters 'a', 'x', 'u' and 'z' are 4, 2, 1 and 1, respectively. We may either encode the symbols as {'a'=0, 'x'=10, 'u'=110, 'z'=111}, or in another way as {'a'=1, 'x'=01, 'u'=001, 'z'=000}, both compress the string into 14 bits. Another set of code can be given as {'a'=0, 'x'=11, 'u'=100, 'z'=101}, but {'a'=0, 'x'=01, 'u'=011, 'z'=001} is NOT correct since "aaaxuaxz" and "aazuaxax" can both be decoded from the code 00001011001001. The students are submitting all kinds of codes, and I need a computer program to help me determine which ones are correct and which ones are not.  8   9 Input Specification: 10  11 Each input file contains one test case. For each case, the first line gives an integer N (2 <= N <= 63), then followed by a line that contains all the N distinct characters and their frequencies in the following format: 12  13 c[1] f[1] c[2] f[2] ... c[N] f[N] 14 where c[i] is a character chosen from {'0' - '9', 'a' - 'z', 'A' - 'Z', '_'}, and f[i] is the frequency of c[i] and is an integer no more than 1000. The next line gives a positive integer M (<=1000), then followed by M student submissions. Each student submission consists of N lines, each in the format: 15  16 c[i] code[i] 17 where c[i] is the i-th character and code[i] is a string of '0's and '1's. 18  19 Output Specification: 20  21 For each test case, print in each line either “Yes” if the student’s submission is correct, or “No” if not. 22  23 Sample Input: 24 7 25 A 1 B 1 C 1 D 3 E 3 F 6 G 6 26 4 27 A 00000 28 B 00001 29 C 0001 30 D 001 31 E 01 32 F 10 33 G 11 34 A 01010 35 B 01011 36 C 0100 37 D 011 38 E 10 39 F 11 40 G 00 41 A 000 42 B 001 43 C 010 44 D 011 45 E 100 46 F 101 47 G 110 48 A 00000 49 B 00001 50 C 0001 51 D 001 52 E 00 53 F 10 54 G 11 55 Sample Output: 56 Yes 57 Yes 58 No 59 No 60 */ 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64  65 #define MinData 0 66  67 typedef struct TreeNode 68 { 69     int Weight; 70     struct TreeNode * Left, * Right; 71 }HuffmanTree, * pHuffmanTree; 72 typedef struct HeapStruct 73 { 74     pHuffmanTree Elements; 75     int Size; 76     int Capacity; 77 }MinHeap, * pMinHeap; 78  79 pMinHeap Create(int MaxSize); 80 void Insert(pMinHeap pH, HuffmanTree item); 81 pHuffmanTree Huffman(pMinHeap pH); 82 pHuffmanTree DeleteMin(pMinHeap pH); 83 int getWPL(pHuffmanTree pT, int layer, int WPL); 84  85 int main() 86 { 87 //    freopen("in.txt", "r", stdin); // for test 88     int N, i; // get input 89     scanf("%d", &N); 90     int a[N]; 91     char ch; 92     for(i = 0; i < N; i++) 93     { 94         getchar(); 95         scanf("%c", &ch); 96         scanf("%d",&a[i]); 97     } 98      99     int WPL = 0; // build min-heap and Huffman tree100     pMinHeap pH;101     HuffmanTree T;102     pH = Create(N);103     for(i = 0; i < N; i++)104     {105         T.Weight = a[i];106         T.Left = NULL;107         T.Right = NULL;108         Insert(pH, T);    109     }110     pHuffmanTree pT;111     pT = Huffman(pH);112     113     WPL = getWPL(pT, 0, WPL); // compare WPL114     int M, j, k;115     scanf("%d", &M);116     int w[M], flag[M];117     char s[N][N + 2];118     for(i = 0; i < M; i++)119     {120         w[i] = 0;121         flag[i] = 0;122         for(j = 0; j < N; j++)123         {124             getchar();125             scanf("%c", &ch);126             scanf("%s", s[j]);127             w[i] += strlen(s[j]) * a[j];128         }129         if(w[i] == WPL)130         {131             flag[i] = 1;132             for(j = 0; j < N; j++)133             {134                 for(k = j + 1; k < N; k++)135                 {136                     if(strlen(s[j]) != strlen(s[k]))137                     {138                         if(strlen(s[j]) >strlen(s[k]))139                             if(strstr(s[j], s[k]) == s[j])140                             {141                                 flag[i] = 0;142                                 break;143                             }144                         else145                             if(strstr(s[k], s[j]) == s[k])146                             {147                                 flag[i] = 0;148                                 break;149                             }150                     }151                 }152             }153         }154     }155     156     for(i = 0; i < M; i++)157     {158         if(flag[i])159             printf("Yes\n");160         else161             printf("No\n");162     }163 //    fclose(stdin); // for test164     return 0;165 }166 167 pMinHeap Create(int MaxSize)168 {169     pMinHeap pH = (pMinHeap)malloc(sizeof(MinHeap));170     pH->Elements = (pHuffmanTree)malloc((MaxSize + 1) * sizeof(HuffmanTree));171     pH->Size = 0;172     pH->Capacity = MaxSize;173     pH->Elements[0].Weight = MinData;174     175     return pH;176 }177 178 void Insert(pMinHeap pH, HuffmanTree item)179 {180     int i;181     182     i = ++pH->Size;183     for(; pH->Elements[i / 2].Weight > item.Weight; i /= 2)184         pH->Elements[i] = pH->Elements[i / 2];185     pH->Elements[i] = item;186 }187 188 pHuffmanTree Huffman(pMinHeap pH)189 {190     int i;191     pHuffmanTree pT;192     193     for(i = 1; i < pH->Capacity; i++)194     {195         pT = (pHuffmanTree)malloc(sizeof(HuffmanTree));196         pT->Left = DeleteMin(pH);197         pT->Right = DeleteMin(pH);198         pT->Weight = pT->Left->Weight + pT->Right->Weight;199         Insert(pH, *pT);200     }201     pT = DeleteMin(pH);202     203     return pT;204 }205 206 pHuffmanTree DeleteMin(pMinHeap pH)207 {208     int Parent, Child;209     pHuffmanTree pMinItem;210     HuffmanTree temp;211     212     pMinItem = (pHuffmanTree)malloc(sizeof(HuffmanTree));213     *pMinItem = pH->Elements[1];214     temp = pH->Elements[pH->Size--];215     for(Parent = 1; Parent * 2 <= pH->Size; Parent = Child)216     {217         Child = Parent * 2;218         if((Child != pH->Size) && (pH->Elements[Child].Weight > pH->Elements[Child + 1].Weight))219             Child++;220         if(temp.Weight <= pH->Elements[Child].Weight)221             break;222         else223             pH->Elements[Parent] = pH->Elements[Child];224     }225     pH->Elements[Parent] = temp;226     227     return pMinItem;228 }229 230 int getWPL(pHuffmanTree pT, int layer, int WPL)231 {232     if(pT->Left == NULL && pT->Right == NULL)233         WPL += layer * pT->Weight;234     else235     {236         WPL = getWPL(pT->Left, layer + 1, WPL);237         WPL = getWPL(pT->Right, layer + 1, WPL);238     }239     240     return WPL;241 }