Compilare: main.cpp: In function 'int main()': main.cpp:39:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < pos[i].size(); ++j) ~~^~~~~~~~~~~~~~~ main.cpp:41:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = j; k < pos[i].size(); ++k) ~~^~~~~~~~~~~~~~~ main.cpp:56:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k + 1 == pos[i].size()) ~~~~~~^~~~~~~~~~~~~~~~ main.cpp:30:9: warning: unused variable 'rad' [-Wunused-variable] int rad = (int)sqrt(n); ^~~