Compilare: main.cpp: In function 'long long int solve(int, int)': main.cpp:15:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i > d.size()){ ~~^~~~~~~~~~ main.cpp:16:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == d.size()){ ~~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:51:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i <= d.size()){ ~~^~~~~~~~~~~