https://www.codeeval.com/open_challenges/2

longest_lines.cpp

#include <iostream>
#include <sstream>
#include <fstream>
#include <queue>

using namespace std;

struct OrderByLength {
    bool operator() (string const &a, string const &b) {
        return a.length() < b.length();
    }
};

int main(int argc, char *argv[]) {
    if (argc < 2) return -1;

    ifstream datafile(argv[1]);
    priority_queue<string, vector<string>, OrderByLength> lines;
    string line;
    int count = 0;

    while (getline(datafile, line)) {
        if (line.length() < 1)
            continue;

        if (count == 0) {
            istringstream splitter(line);
            splitter >> count;
            continue;
        }

        lines.push(line);
    }

    for (int x = 0; x < count; x++) {
        cout << lines.top() << endl;
        lines.pop();
    }

    return 0;
}