Compilare: main.cpp: In function 'void solve(long long int*)': main.cpp:15:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < s.size(); i++) { ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:42:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < s.size() - 1; i++) ~~^~~~~~~~~~~~~~