vector print and kasai function

//
// Example of showing how to pass a vector to a function (kasai) and print it by various methods
// g++-7 -std=c++17 kasai.cpp -o kasai
//
#include <iostream>
#include <string>
#include <vector>
// select the options to print a vector (default overloading the << operator to recognise the ostream object)
// #define WITH_FUNCTION
// #define OPTION_1
// #define OPTION_2
#define OPTION_3
#if defined(OPTION_3) && defined(WITH_FUNCTION)
#include <algorithm>
#include <iterator>
#endif
using namespace std;

vector<int> kasai(string s, vector<int> &sa)
{
    int n=s.size(),k=0;
    vector<int> lcp(n,0);
    vector<int> rank(n,0);

    for(int i=0; i<n; i++) rank[sa[i]]=i;

    for(int i=0; i<n; i++, k?k--:0)
    {
        if(rank[i]==n-1) {k=0; continue;}
        int j=sa[rank[i]+1];
        while(i+k<n && j+k<n && s[i+k]==s[j+k]) k++;
        lcp[rank[i]]=k;
    }
    return lcp;
}


#if defined(WITH_FUNCTION)
void printVector(std::vector<int> const &input)
{
#if defined(OPTION_1)
    for (int i = 0; i < input.size(); i++) {
        std::cout << input.at(i) << ' ';
    }
#elif defined(OPTION_2)
    for (auto const &i: input) {
        std::cout << i << " ";
    }
#elif defined(OPTION_3)
    std::copy(input.begin(),
              input.end(),
              std::ostream_iterator<int>(std::cout, " "));
#endif
}
#else
std::ostream &operator<<(std::ostream &os, const std::vector<int> &input)
{
    for (auto const &i: input) {
        os << i << " ";
    }
    return os;
}
#endif

main()
{
    std::string myInput;

    cout << "enter the string : " << endl;
    getline(cin,myInput);
    vector<int> vec(myInput.size(),0);
    auto lcp = kasai(myInput, vec);
#if defined(WITH_FUNCTION)
    printVector(lcp);
#else
    cout << " the vector now prints normally " << lcp << endl;
#endif
}