mere.cpp: In function 'void dfs(int)': mere.cpp:12: warning: comparison between signed and unsigned integer expressions mere.cpp: In function 'int main()': mere.cpp:24: warning: suggest explicit braces to avoid ambiguous 'else' mere.cpp:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result mere.cpp:18: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result mere.cpp:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mere.cpp:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result