View Compilation Error

0_0_37896456_20680.cpp: In function 'int getM(int)':
0_0_37896456_20680.cpp:19:10: error: 'len' was not declared in this scope
  while(i<len&&j<len&&k<len){
          ^
0_0_37896456_20680.cpp:20:9: error: 's' was not declared in this scope
   int t=s[(j+k)%len]-s[(i+k)%len];
         ^
0_0_37896456_20680.cpp: In function 'int main()':
0_0_37896456_20680.cpp:41:3: error: 'ansmax' was not declared in this scope
   ansmax=getM(0);
   ^
0_0_37896456_20680.cpp:42:3: error: 'ansmin' was not declared in this scope
   ansmin=getM(1);
   ^