Compilare: user.cpp: In function ‘void Tarjan(int)’: user.cpp:17:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, fiu; ^ user.cpp:17:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, fiu; ^ user.cpp: In function ‘int main()’: user.cpp:71:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( j = 0; j < Sol[ i ].size(); ++j ) { ~~^~~~~~~~~~~~~~~~~ user.cpp:53:27: warning: unused variable ‘k’ [-Wunused-variable] int n, m, x, y, i, j, k; ^ user.cpp:50:36: 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:51:38: 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:55:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d", &n, &m ); ^ user.cpp:58:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d", &x, &y ); ^