Compilare: main.cpp: In function 'void solve_p1()': main.cpp:30:6: warning: unused variable 'i' [-Wunused-variable] {int i; ^ main.cpp: In function 'int main()': main.cpp:40:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < s.size(); i++) ~~^~~~~~~~~~ main.cpp:50:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < s.size(); j++) ~~^~~~~~~~~~