Compilare: user.cpp: In function ‘bool solve(std::string)’: user.cpp:9:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < s.size(); ++ i) ^ user.cpp:13:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(cnt == 0 || cnt == s.size()) ^ user.cpp:15:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(cnt <= s.size() / 2) ^ user.cpp:16:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < s.size(); ++ i) ^ user.cpp:23:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < s.size() - 1; ++ i) ^ user.cpp:31:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < s.size(); ++ i) ^ user.cpp: In function ‘int main()’: user.cpp:80:12: warning: unused variable ‘i’ [-Wunused-variable] int t, i; ^ user.cpp:78:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("csir.in", "r", stdin); ^ user.cpp:79:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("csir.out", "w", stdout); ^