Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:62:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < v[ x ].size(); ++i ){ ^ user.cpp:68:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < v[ x ].size(); ++i ){ ^ user.cpp:70:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < v[ y ].size(); ++j ){ ^ user.cpp:59:9: warning: unused variable ‘n’ [-Wunused-variable] int n, i, j, y, c; ^ user.cpp:59:21: warning: unused variable ‘c’ [-Wunused-variable] int n, i, j, y, c; ^ user.cpp: In function ‘int main()’: user.cpp:28:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.in","r",stdin); ^ user.cpp:29:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.out","w",stdout); ^ user.cpp:33:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:35:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^