/in/foo.cc: In function 'int main()':
/in/foo.cc:21:32: error: 'maxn' was not declared in this scope
     t=0,p=rand()%a[i]+1+rand()%maxn; 
                                ^~~~
/in/foo.cc:21:32: note: suggested alternative: 'main'
     t=0,p=rand()%a[i]+1+rand()%maxn; 
                                ^~~~
                                main