Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs1(int)’: user.cpp:38: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:50: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs3(int)’: user.cpp:66: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:134: warning: comparison between signed and unsigned integer expressions user.cpp:150: warning: comparison between signed and unsigned integer expressions user.cpp:157: warning: comparison between signed and unsigned integer expressions user.cpp:82: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:83: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:84: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:88: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result