/in/foo.cc: In function 'void merge(MST&, MST&, MST&)':
/in/foo.cc:86:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
     if(j>ae||k<=be&&j->z>k->z)ca=0;
              ~~~~~^~~~~~~~~~~
/in/foo.cc:101:18: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     vis[i]=val[i]=0;
            ~~~~~~^~