Oценка и обоснование сложности получившегося алгоритма в O-нотации

[zoichik]

Мне нужно написать оценку и обоснование сложности получившегося алгоритма в O-нотации. Объясните, пожалуйста, как это сделать.

#include <iostream> 
#include <fstream> 
#include <string> 
#include <sstream> 
#include <vector> 
#include <map> 
#include <chrono> 
 
using namespace std; 
 
vector<string> getSourceText(); 
vector<string> getWords(const vector<string>& lines); 
void bubbleSort(vector<string>& words); 
unsigned long long sortWordsByLength(vector<string>& words); 
void writeResult(vector<string>& words); 
void analysis(string task, const vector<string>& lines, const vector<string>& words, unsigned long long elapseTime); 
void analysisImpl(ostream &out, string task, const vector<string>& lines, const vector<string>& words, unsigned long long elapseTime); 
 
int main() 
{ 
    string task = "Variant 7. Latin, sort by length, descending order, allow number, bubble sort"; 
    vector<string> lines = getSourceText(); 
    vector<string> words = getWords(lines); 
    auto elapsed = sortWordsByLength(words); 
    writeResult(words); 
    analysis(task, lines, words, elapsed); 
     
    return 0; 
} 
 
vector<string> getSourceText() 
{ 
    cout << "Input path to file: "; 
    string pathToFile; 
    getline(cin, pathToFile); 
 
    ifstream in(pathToFile); 
 
    if (!in.is_open()) { 
        return vector<string>(); 
    } 
 
    string line; 
    vector<string> lines; 
 
    while (getline(in, line)) { 
        lines.push_back(line); 
    } 
 
    in.close(); 
 
    return lines; 
} 
 
vector<string> getWords(const vector<string> &lines) 
{ 
    string validSymbols = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"; 
 
    string line; 
    vector<string> words; 
 
    for (auto line : lines) { 
        istringstream iss(line); 
        string word; 
 
        while (iss >> word) { 
            size_t pos = 0; 
            while ((pos = word.find_first_not_of(validSymbols, pos)) != string::npos) { 
                word.erase(pos, 1); 
            } 
 
            if (!word.empty()) 
                words.push_back(word); 
        } 
    } 
 
    return words; 
} 
 
void writeResult(vector<string>& words) { 
    ofstream out("result.txt"); 
 
    for (auto word : words) 
        out << word << endl; 
 
    out.close(); 
} 
 
void bubbleSort(vector<string>& words) 
{ 
    for (int i = 0; i < words.size(); i++) { 
        for (int j = 0; j < words.size() - 1; j++) { 
            if (words[j].length() < words[j + 1].length()) { 
                swap(words[j], words[j + 1]); 
            } 
        } 
    } 
} 
 
unsigned long long sortWordsByLength(vector<string>& words) 
{ 
    auto start = std::chrono::steady_clock::now(); 
    bubbleSort(words); 
    auto end = std::chrono::steady_clock::now(); 
    return std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count(); 
} 
 
void analysis(string task, const vector<string>& lines, const vector<string>& words, unsigned long long elapsedTimeMs) 
{ 
    ofstream out("analysis.txt"); 
    analysisImpl(out, task, lines, words, elapsedTimeMs); 
    out.close(); 
 
    analysisImpl(cout, task, lines, words, elapsedTimeMs); 
} 
 
void analysisImpl(ostream &out, string task, const vector<string>& lines, const vector<string>& words, unsigned long long elapsedTimeMs) 
{ 
    out << "Source text:" << endl; 
 
    for (auto line : lines) 
        out << line << endl; 
 
    out << endl; 
 
    out << task << endl; 
    out << "Count words : " << words.size() << endl; 
    out << "Sort time : " << elapsedTimeMs << " ms" << endl << endl; 
     
    out << "Statistic. Count words specify length:" << endl; 
    map<size_t, size_t> appears; 
    for (int i = 0; i < words.size(); ++i) { 
        ++appears[words[i].length()]; 
    } 
 
    for (auto pair : appears) 
        out << "Length word " << pair.first << " appears " << pair.second << endl; 
}