net.cpp: In function 'void dfs(int, int)':
net.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) dfs(g[s][i],s);
~^~~~~~~~~~~~
net.cpp: In function 'int main()':
net.cpp:34:34: error: 's' was not declared in this scope
if(l%2==0) printf("%d %d",s,k[l-1]);
^
net.cpp:21:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&n);
~~~~~^~~~~~~~~
net.cpp:24:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&v1,&v2);
~~~~~^~~~~~~~~~~~~~~~