Compilare: user.cpp: In function ‘void dfs(int, int&)’: user.cpp:24: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs1(int)’: user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs11(int)’: user.cpp:55: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:71: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:247: warning: suggest explicit braces to avoid ambiguous ‘else’ user.cpp:293: warning: suggest explicit braces to avoid ambiguous ‘else’