biochips.cpp: In function 'void dfs(int)':
biochips.cpp:16:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i<g[v].size();i++){
~^~~~~~~~~~~~
biochips.cpp: In function 'int main()':
biochips.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&n,&m);
~~~~~^~~~~~~~~~~~~~
biochips.cpp:29:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&x,&y);
~~~~~^~~~~~~~~~~~~~
biochips.cpp:36:8: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
dfs(root);
~~~^~~~~~