View Compilation Error

0_0_36716661_21725.cpp: In function 'int main()':
0_0_36716661_21725.cpp:13:3: error: 'in' was not declared in this scope
   in
   ^
0_0_36716661_21725.cpp: At global scope:
0_0_36716661_21725.cpp:20:3: error: expected unqualified-id before 'if'
   if (flag) //A和B后K位相等
   ^
0_0_36716661_21725.cpp:22:3: error: expected unqualified-id before 'else'
   else
   ^
0_0_36716661_21725.cpp:24:2: error: expected declaration before '}' token
  }
  ^