Compilare: main.cpp: In function 'int main()': main.cpp:47:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int ii = 0; ii < a[i].size(); ++ii) { ~~~^~~~~~~~~~~~~ main.cpp:48:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int jj = ii + 1; jj < a[i].size(); ++jj) { ~~~^~~~~~~~~~~~~ main.cpp:53:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < a[i].size() && has > 0; ++j) { ~~^~~~~~~~~~~~~