ac1055.pas

同济大学 Online在线题库 AC源代码合集 程序设计竞赛必看资料

program tju1055;
const
  maxn=100;
var
  adj:array[1..maxn,1..maxn]of boolean;
  v:array[1..maxn]of boolean;
  n,x,y,z:byte;
  ok:boolean;
procedure floodfill(x:byte);
  var
    i:byte;
  begin
    v[x]:=true;
    if x=y then exit;
    for i:=1 to n do
      if not v[i] and adj[x,i] and (i<>z) then begin
        floodfill(i);
        if v[y] then exit;
      end;
  end;
begin
  repeat
    fillchar(adj,sizeof(adj),0);
    read(n);
    repeat
      read(x,y);
      if x=0 then break;
      adj[x,y]:=true;adj[y,x]:=true;
    until false;
    read(x,y);

    ok:=false;
    for z:=1 to n do
      if (z<>x) and (z<>y) then begin
        fillchar(v,sizeof(v),0);
        floodfill(x);
        if not v[y] then begin
          writeln(z);
          ok:=true;
          break;
        end;
      end;

    if not ok then writeln('No solution');
  until seekeof;
end.