View Compilation Error

0_0_37689869_12485.cpp: In instantiation of 'solve()::<lambda(auto:1, long long int, long long int, bool)> [with auto:1 = solve()::<lambda(auto:1, long long int, long long int, bool)>]':
0_0_37689869_12485.cpp:113:39:   required from here
0_0_37689869_12485.cpp:99:30: error: 'f' was not declared in this scope
         if (lim == false && f[len][sta]) {
                              ^
0_0_37689869_12485.cpp:109:10: error: 'f' was not declared in this scope
         f[len][sta] = res;
          ^