/in/foo.cc: In function 'int read()':
/in/foo.cc:6:2: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
  while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar(); return x;
  ^~~~~
/in/foo.cc:6:53: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'while'
  while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar(); return x;
                                                     ^~~~~~
/in/foo.cc: In function 'int sap(int, int, int)':
/in/foo.cc:26:14: warning: 'h' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(i)cur[x]=i,pre[e[i].to]=x,x=e[i].to;
        ~~~~~~^~