Compilare: main.cpp: In function 'bool verify(int)': main.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < b.size(); i++) { ~~^~~~~~~~~~ main.cpp:29:99: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (minim == last || frcv[minim][b[i] - 'a'] - frcv[last][b[i] - 'a'] < key || (n - minim < (b.size() - i - 1) * key)) ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~