biperm.cpp: In function 'void dfs(int, int)': biperm.cpp:16: warning: comparison between signed and unsigned integer expressions biperm.cpp:19: warning: comparison between signed and unsigned integer expressions biperm.cpp:36: warning: comparison between signed and unsigned integer expressions biperm.cpp:39: warning: comparison between signed and unsigned integer expressions biperm.cpp: In function 'int main()': biperm.cpp:106: warning: comparison between signed and unsigned integer expressions biperm.cpp:58: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result biperm.cpp:59: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result biperm.cpp:60: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result biperm.cpp:62: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result biperm.cpp:64: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result