Compilare: main.cpp: In function 'int solve(int, int)': main.cpp:12:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[j].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:31:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[0].size();i++) ~^~~~~~~~~~~~