graphgame.cpp: In function 'void dfs(int, int)': graphgame.cpp:16: warning: comparison between signed and unsigned integer expressions graphgame.cpp: In function 'bool match(int)': graphgame.cpp:27: warning: comparison between signed and unsigned integer expressions graphgame.cpp:32: warning: comparison between signed and unsigned integer expressions graphgame.cpp: In function 'int main()': graphgame.cpp:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result graphgame.cpp:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result