#include <fmt/ranges.h>

#include <iostream>

#include <string>

#include <utility>

using namespace std;

class Solution

{

public:

string mergeAlternately(string word1, string word2)

{

auto it1 = word1.begin();

auto it2 = word2.begin();

while (it2 != word2.end()) {

if (it1 != word1.end())

++it1;

it1 = word1.insert(it1, *it2);

if (it1 != word1.end())

++it1;

++it2;

}

return word1;

}

};

int main()

{

Solution sol;

// test cases

std::pair<string, string> test1 = {"abc", "pqr"};

std::pair<string, string> test2 = {"ab", "pqrs"};

std::pair<string, string> test3 = {"abcd", "pq"};

std::pair<string, string> test4 = {"dajmknzgidixqgt", "nahamebx"};

for (auto test : {test4, test1, test2, test3}) {

auto result = sol.mergeAlternately(test.first, test.second);

fmt::print("Before: {} {} After: {}\n", test.first, test.second, result);

}

}