police.cpp: In function 'int dfs(int)': police.cpp:12: warning: comparison between signed and unsigned integer expressions police.cpp:25: warning: no return statement in function returning non-void police.cpp: In function 'int main()': police.cpp:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result police.cpp:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result police.cpp:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result police.cpp:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result