/in/foo.cc:10:8: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
 }e[maxm+maxm<<1];
        ^
/in/foo.cc: In function 'void topu_()':
/in/foo.cc:54:17: warning: unused variable 'v' [-Wunused-variable]
             int v=e[i].v,w=e[i].w;
                 ^