Accepted
/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<a[x].size();i++) //走不下去就是叶子结点
~^~~~~~~~~~~~
/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<a[x].size();i++) //走不下去就是叶子结点
~^~~~~~~~~~~~
