Compilare: user.cpp: In function ‘void Query()’: user.cpp:60:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( m >= V[ Q[1] ].size() ) ^ user.cpp:67:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( m >= V[ Q[i] ].size() || V[ Q[i] ][ m ] != V[ Q[1] ][ m ] ) ^ user.cpp: In function ‘int main()’: user.cpp:83:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &n, &m); ^ user.cpp:86:30: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(S, 2002, stdin); // introduce a string in the trie ^ user.cpp:91:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); // query ^ user.cpp:93:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &Q[j]); ^