Compilare: user.cpp: In function ‘int main()’: user.cpp:42:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < sol.size(); ++i ){ ^ user.cpp:44:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < sol[ i ].size(); ++j ) printf("%d ",sol[ i ][ j ]); ^ user.cpp:30:27: warning: unused variable ‘s’ [-Wunused-variable] int n, m, i, j, x, y, s, t, d; ^ user.cpp:30:30: warning: unused variable ‘t’ [-Wunused-variable] int n, m, i, j, x, y, s, t, d; ^ user.cpp:30:33: warning: unused variable ‘d’ [-Wunused-variable] int n, m, i, j, x, y, s, t, d; ^ user.cpp: In function ‘void tarjan(int)’: user.cpp:60:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < v[ nod ].size(); ++i ){ ^ user.cpp:54:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, ok, fiu; ^ user.cpp: In function ‘int main()’: user.cpp:27:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in","r",stdin); ^ user.cpp:28:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out","w",stdout); ^ user.cpp:32:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:34:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^