tower.cpp: In function 'int main()':
tower.cpp:61:9: error: 'sol' was not declared in this scope
61 | sol = (sol*1LL*k)%((int)1e9+9);
| ^~~
tower.cpp:63:13: error: 'sol' was not declared in this scope
63 | cout << sol << '\n';
| ^~~
tower.cpp:57:16: warning: unused variable 'ans' [-Wunused-variable]
57 | int r = 0, ans = 1;
| ^~~
tower.cpp: In function 'void IO(std::string)':
tower.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
44 | freopen((s+".in").c_str(),"r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tower.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
45 | freopen((s+".out").c_str(),"w",stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~