View Compilation Error

0_0_38769467_18475.cpp: In function 'void Solve()':
0_0_38769467_18475.cpp:2:22: error: 'n' was not declared in this scope
    2 |         scanf("%d", &n);
      |                      ^
0_0_38769467_18475.cpp:2:9: error: 'scanf' was not declared in this scope
    2 |         scanf("%d", &n);
      |         ^~~~~
0_0_38769467_18475.cpp:4:29: error: 'a' was not declared in this scope
    4 |                 scanf("%d", a+i);
      |                             ^
0_0_38769467_18475.cpp:6:9: error: 'a' was not declared in this scope
    6 |         a[n+1] = -1;
      |         ^