src.cpp:3:33: error: size of array 'a' is too large
long long int n, i, a[1000000009];
^
src.cpp: In function 'int main()':
src.cpp:11:10: error: 'a' was not declared in this scope
cin>>a[i];
^
src.cpp:13:6: error: 'a' was not declared in this scope
sort(a+1,a+n+1);
^