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copied!<p>I suspect that this is because of the way <code>std::vector</code> gets resized during the process of a push_back() function call. If you try using <code>std::list</code> or <code>std::vector::reserve()</code> to reserve enough space for the sentences, you should get a much better performance. Or you could use a combination of both like below for split1():</p> <pre><code>void split1(vector<string> &tokens, const string &str, const string &delimiters = " ") { // Skip delimiters at beginning string::size_type lastPos = str.find_first_not_of(delimiters, 0); // Find first non-delimiter string::size_type pos = str.find_first_of(delimiters, lastPos); list<string> token_list; while (string::npos != pos || string::npos != lastPos) { // Found a token, add it to the list token_list.push_back(str.substr(lastPos, pos - lastPos)); // Skip delimiters lastPos = str.find_first_not_of(delimiters, pos); // Find next non-delimiter pos = str.find_first_of(delimiters, lastPos); } tokens.assign(token_list.begin(), token_list.end()); } </code></pre> <p><em>EDIT</em>: The other obvious thing I see is that Python variable <code>dummy</code> gets <em>assigned</em> each time but not modified. So it's not a fair comparison against C++. You should try modifying your Python code to be <code>dummy = []</code> to initialize it and then do <code>dummy += line.split()</code>. Can you report the runtime after this?</p> <p><strong>EDIT2</strong>: To make it even more fair can you modify the while loop in C++ code to be:</p> <pre><code> while(cin) { getline(cin, input_line); std::vector<string> spline; // create a new vector //I'm trying one of the two implementations, per compilation, obviously: // split1(spline, input_line); split2(spline, input_line); count++; }; </code></pre>

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