View Compilation Error

0_0_38616958_12225.c:2:1: error: unknown type name 'using'
 using namespace std;
 ^~~~~
0_0_38616958_12225.c:2:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^~~
0_0_38616958_12225.c:4:5: error: variably modified 'a' at file scope
 int a[maxn];
     ^
0_0_38616958_12225.c: In function 'solve':
0_0_38616958_12225.c:14:13: error: 'cout' undeclared (first use in this function)
  if(a[0]>0) cout<<"Alice"<<endl;
             ^~~~
0_0_38616958_12225.c:14:13: note: each undeclared identifier is reported only once for each function it appears in
0_0_38616958_12225.c:14:28: error: 'endl' undeclared (first use in this function)
  if(a[0]>0) cout<<"Alice"<<endl;
                            ^~~~