Compilare: user.cpp: In function ‘int bfs(int, int)’: user.cpp:33:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<m[no].size();i++) ^ user.cpp:41:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:143:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<t.size();i++) bfs(i+1,t[i]); ^ user.cpp:130:17: warning: unused variable ‘j’ [-Wunused-variable] int i,n1,n2,j; ^ user.cpp:147:9: warning: unused variable ‘improve’ [-Wunused-variable] int improve=1; ^ user.cpp:131:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in","r",stdin); ^ user.cpp:133:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m1,&u,&fin); ^ user.cpp:134:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=u;i++) { scanf("%d",&n1); t.pb(n1); } ^ user.cpp:137:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n1,&n2); ^