/in/foo.cc: In function 'int main()':
/in/foo.cc:35:13: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   if(n==0&&m==0&t==0)
            ~^~~
/in/foo.cc:61:15: warning: 'l2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   dfs(l1,l2,0);
               ^
/in/foo.cc:61:15: warning: 'l1' may be used uninitialized in this function [-Wmaybe-uninitialized]