Compilare: main.cpp: In function 'int main()': main.cpp:34:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); i++) ~~^~~~~~~~~~ main.cpp:48:109: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s[pos[c - 'a'][firstPos]] == c && pos[c - 'a'][firstPos] >= prevPos && firstPos + k - 1 < pos[c - 'a'].size()) ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~