foo.cc:2:5: error: 'cin' does not name a type
     cin>>n;
     ^~~
foo.cc:3:5: error: expected unqualified-id before 'for'
     for(int i=1;i<=n;i++)
     ^~~
foo.cc:3:17: error: 'i' does not name a type
     for(int i=1;i<=n;i++)
                 ^
foo.cc:3:22: error: 'i' does not name a type
     for(int i=1;i<=n;i++)
                      ^
foo.cc:9:5: error: 'f' does not name a type
     f[1]=a[1];
     ^
foo.cc:11:5: error: expected unqualified-id before 'for'
     for(int i=2;i<=n;i++)
     ^~~
foo.cc:11:17: error: 'i' does not name a type
     for(int i=2;i<=n;i++)
                 ^
foo.cc:11:22: error: 'i' does not name a type
     for(int i=2;i<=n;i++)
                      ^
foo.cc:30:5: error: 'cout' does not name a type
     cout<<len;
     ^~~~
foo.cc:31:1: error: expected declaration before '}' token
 }
 ^

正在同步测试数据，请稍后
自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。