Algorithm to merge multiple sorted sequences into one sorted sequence in C++ [closed]

Answer 1

The C++ standard library contains std::merge

std::vector v1 { 1,2,5,7 }, 
                 v2 { 3,6,9 }, 
                 out;

std::merge(v1.begin(), v1.end(), 
           v2.begin(), v2.end(), 
           std::back_inserter(out));

http://en.cppreference.com/w/cpp/algorithm/merge