Compilare: user.cpp: In member function ‘bool nrx_trie::verify1(nrx_trie::trie_node*, char*, int)’: user.cpp:47:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( node -> occurrence.count() == K ) ^ user.cpp: In function ‘int main()’: user.cpp:86:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "sub.in" , "r", stdin ); ^ user.cpp:87:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "sub.out", "w", stdout ); ^ user.cpp:89:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &N ); ^ user.cpp:91:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%s", A[i] + 1 ); ^ user.cpp:98:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &M ); ^ user.cpp:100:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%s", B[i] + 1 ); ^