Compilare: user.cpp: In function ‘int solve()’: user.cpp:102:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < rad.size(); i++) ^ user.cpp:105:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < rad.size(); i++) ^ user.cpp:108:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(mch.size() != N - 1) ^ user.cpp: In function ‘int main()’: user.cpp:129:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < mch.size(); i++) ^ user.cpp: In function ‘char gchar()’: user.cpp:17:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] cnt = 0, fread(buff, buffer, 1, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:116:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("revolve.in", "r", stdin); ^ user.cpp:117:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("revolve.out", "w", stdout); ^