Compilare: user.cpp: In function 'void dfs(int)': user.cpp:30: warning: comparison between signed and unsigned integer expressions user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void solve()': user.cpp:56: warning: comparison between signed and unsigned integer expressions user.cpp:70: warning: comparison between signed and unsigned integer expressions user.cpp:80: warning: comparison between signed and unsigned integer expressions user.cpp:97: warning: comparison between signed and unsigned integer expressions user.cpp:107: warning: comparison between signed and unsigned integer expressions user.cpp:117: warning: comparison between signed and unsigned integer expressions user.cpp:135: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void show()': user.cpp:141: warning: unused variable 'j'