bile1.cpp: In function 'void dfs1(int)': bile1.cpp:20: warning: comparison between signed and unsigned integer expressions bile1.cpp: In function 'void dfs2(int)': bile1.cpp:32: warning: comparison between signed and unsigned integer expressions bile1.cpp: In function 'int main()': bile1.cpp:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result bile1.cpp:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result bile1.cpp:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result bile1.cpp:47: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result