View Compilation Error

0_0_23509710_31767.cpp: In function 'void dfs(char)':
0_0_23509710_31767.cpp:21:10: error: invalid types 'char[int]' for array subscript
   if (a[i] == 0 && b[i].head == a)
          ^
0_0_23509710_31767.cpp:23:7: error: invalid types 'char[int]' for array subscript
    a[i] = 1;
       ^
0_0_23509710_31767.cpp:25:7: error: invalid types 'char[int]' for array subscript
    a[i] = 0;
       ^