Accepted
/in/foo.cc: In function 'void dfs(int)': /in/foo.cc:17:20: 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:17:20: 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 ~~^~~~~~~~~~~~~