Compilare: user.cpp: In function ‘void bfs(int, int)’: user.cpp:31:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j=0;j<g[u].size();j++ ) ^ user.cpp: In function ‘int main()’: user.cpp:48:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "bfs.in", "r", stdin ); ^ user.cpp:49:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "bfs.out", "w", stdout ); ^ user.cpp:53:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d%d", &n, &m, &s ); ^ user.cpp:57:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d", &u, &v ); ^