哪种方法更适合霍夫曼编码 我想读取字符及其频率

which method is more suitable for huffman encoding i want to read chars with their frequency

本文关键字：读取 字符 频率 编码 方法 霍夫曼      更新时间：2023-10-16

两个从字符串中读取字符的循环

void ReadCharWithFreq(string str){ 
    int n = str.size();  
    int count = 0;
    // loops to read all char from string and frequency
    for(int i = 0;i<n;i++){
        for(int x =0;x<n;x++ ){
            if(str[i]==str[x]){
                count++;
            }
        }       
        //enqueue char with frequency
        enqueue(str[i],count);
        count=0;
    }
} //end of function

相同的功能，不同的方法使用堆数组 freq[] 和模因集我不明白模因集（数组，整数，整数）的功能

void ReadCharWithFreq(string str){ 
    int n = str.size(); 
    int SIZE = 40;
    int spf=0;
    memset(freq, 0, sizeof(freq));
    for (int i = 0; i < n; i++){
        freq[str[i] - 'a']++; 
    }
    for (int i = 0; i < n; i++) { 
        if (freq[str[i] - 'a'] != 0) { 
            cout << str[i] <<" "<< freq[str[i] - 'a'] << " - >"; 
            enqueue(str[i], freq[str[i] - 'a']);
            freq[str[i] - 'a'] = 0;
        } 
    } 
} //end of function

以上哪一种算法更准确高效我想从字符串中读取所有字符并计算它们的出现次数/频率

我会使用一个空间足以容纳您可能遇到的所有字符计数的std::array：

#include <array>
#include <limits>
constexpr size_t ArrSize = std::numeric_limits<unsigned char>::max()+1;
std::array<unsigned char, ArrSize> ReadCharWithFreq(const std::string& str){
    std::array<unsigned char, ArrSize> freq{};
    for(unsigned char ch : str)
        freq[ch]++;
    return freq;
}

用法示例：

#include <iostream>
#include <iomanip>
#include <vector>
int main(int argc, char* argv[]) {
    std::vector<std::string> args(argv+1, argv+argc);
    for(const auto& str : args) {
        auto result = ReadCharWithFreq(str);
        for(size_t i=0; i<ArrSize; ++i) {
            if(result[i]) {
                std::cout << std::setw(3) << i << " " << static_cast<char>(i) << " " << static_cast<int>(result[i]) << "n";
                // enqueue here? 
            } 
        }
    }
}
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