Compilare: user.cpp: In function ‘void solve()’: user.cpp:23:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0; i < G [ x ] .size ( ) ; i++ ) ^ user.cpp:34:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = 0; j < G [ y ] .size ( ) ; j++ ) ^ user.cpp: In function ‘void read_data()’: user.cpp:48:9: warning: unused variable ‘j’ [-Wunused-variable] int i, j, a, b; ^ user.cpp:49:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d %d", &N, &M, &X ) ; ^ user.cpp:52:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d", &val [ i ] ) ; ^ user.cpp:58:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d", &a, &b ) ; ^ user.cpp: In function ‘int main()’: user.cpp:68:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "markon.in", "rt", stdin ) ; ^ user.cpp:69:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "markon.out", "wt", stdout ) ; ^