C++

string vector_to_string(vector> &v);

vector_to_string : returns a single string of the argument vector>, where each element is printed as string:long, comma

separated elements. No comma at the end! This vector is convenient for sorting, (can't sort a map) .

input:

2 3 helloworld 

ouput:

hel, ell, llo, low, owo, wor, orl, rld,