View Compilation Error

0_0_32071908_29649.cpp: In function 'int main()':
0_0_32071908_29649.cpp:28:29: error: invalid types 'int[int]' for array subscript
   for(int i=0;i<=26;i++) b[i]=0;
                             ^
0_0_32071908_29649.cpp:30:3: error: 'tail' was not declared in this scope
   tail=1,ans=0;
   ^