Comment implémenter des algorithmes de compression et de décompression de données en C++ ?

#include #include #include #include using namespace std; // Huffman树的节点 struct Node { char ch; int freq; Node* left; Node* right; }; // 用于比较树节点的优先队列 class Compare { public: bool operator() (Node* a, Node* b) { return a->freq > b->freq; } }; // 生成Huffman树 Node* generateHuffmanTree(string text) { // 统计每个字符出现的频率 unordered_map freqTable; for (char ch : text) { freqTable[ch]++; } // 将频率和字符转换为Huffman树节点 priority_queue, Compare> pq; for (auto it = freqTable.begin(); it != freqTable.end(); it++) { Node* node = new Node(); node->ch = it->first; node->freq = it->second; node->left = nullptr; node->right = nullptr; pq.push(node); } // 构建Huffman树 while (pq.size() > 1) { Node* left = pq.top(); pq.pop(); Node* right = pq.top(); pq.pop(); Node* parent = new Node(); parent->ch = ''; parent->freq = left->freq + right->freq; parent->left = left; parent->right = right; pq.push(parent); } return pq.top(); } // 生成Huffman编码表 void generateHuffmanCodeTable(Node* root, string code, unordered_map& codeTable) { if (root == nullptr) { return; } if (root->ch != '') { codeTable[root->ch] = code; } generateHuffmanCodeTable(root->left, code + "0", codeTable); generateHuffmanCodeTable(root->right, code + "1", codeTable); } // 压缩数据 string compressData(string text, unordered_map& codeTable) { string compressedData; for (char ch : text) { compressedData += codeTable[ch]; } return compressedData; } int main() { string text = "Hello, World!"; Node* root = generateHuffmanTree(text); unordered_map codeTable; generateHuffmanCodeTable(root, "", codeTable); string compressedData = compressData(text, codeTable); cout << "Compressed Data: " << compressedData << endl; return 0; }

#include #include #include using namespace std; // 压缩数据 string compressData(string text) { string compressedData; int i = 0; while (i < text.length()) { int len = 0; int offset = 0; for (int j = 0; j < i; j++) { int k = 0; while (i + k < text.length() && text[j + k] == text[i + k]) { k++; } if (k > len) { len = k; offset = i - j; } } if (len > 0) { compressedData += "(" + to_string(offset) + "," + to_string(len) + ")"; i += len; } else { compressedData += text[i]; i++; } } return compressedData; } int main() { string text = "ababaabababbbb"; string compressedData = compressData(text); cout << "Compressed Data: " << compressedData << endl; return 0; }

#include #include #include using namespace std; // 解压缩数据 string decompressData(string compressedData, unordered_map& codeTable) { string decompressedData; string code; for (char ch : compressedData) { code += ch; if (codeTable.count(code) > 0) { decompressedData += codeTable[code]; code = ""; } } return decompressedData; } int main() { string compressedData = "010101001111011001"; unordered_map codeTable = { {"0", 'a'}, {"10", 'b'}, {"110", 'c'}, {"1110", 'd'}, {"1111", 'e'} }; string decompressedData = decompressData(compressedData, codeTable); cout << "Decompressed Data: " << decompressedData << endl; return 0; }

#include #include #include using namespace std; // 解压缩数据 string decompressData(string compressedData) { string decompressedData; int i = 0; while (i < compressedData.length()) { if (compressedData[i] == '(') { int j = i + 1; while (compressedData[j] != ',') { j++; } int offset = stoi(compressedData.substr(i + 1, j - i - 1)); int k = j + 1; while (compressedData[k] != ')') { k++; } int len = stoi(compressedData.substr(j + 1, k - j - 1)); for (int l = 0; l < len; l++) { decompressedData += decompressedData[decompressedData.length() - offset]; } i = k + 1; } else { decompressedData += compressedData[i]; i++; } } return decompressedData; } int main() { string compressedData = "a(1,1)ab(3,3)b(9,2)"; string decompressedData = decompressData(compressedData); cout << "Decompressed Data: " << decompressedData << endl; return 0; }