记录编号	3874	评测结果	AAAWWA
题目名称	[NOIP 2002]过河卒	最终得分	66
用户昵称	zhai	是否通过	未通过
代码语言	Pascal	运行时间	0.018 s
提交时间	2008-10-12 08:53:49	内存使用	0.12 MiB

program pj024;   
  type  
    sz=array[-1..20,-1..20]of int64;   
    fa=record  
      xx,yy:integer;   
    end;   
  const  
    f:array[1..8]of fa=((xx:-2;yy:-1;),(xx:-2;yy:1;),(xx:-1;yy:2;),   
      (xx:1;yy:2;),(xx:2;yy:1;),(xx:2;yy:-1;),(xx:1;yy:-2;),(xx:-1;yy:-2;));   
  var  
    a:sz;   
    f1,f2:text;   
    n,m,x,y:integer;   
    procedure ini;   
      var  
        i,p,q:integer;   
      begin  
        assign(f1,'pj024.in');reset(F1);   
        assign(f2,'pj024.out');rewrite(f2);   
        read(f1,n,m,x,y);   
        close(f1);   
        fillchar(a,sizeof(a),0);   
        a[x,y]:=-1;   
        for i:=1 to 8 do begin  
          p:=x+f[i].xx;   
          q:=y+f[i].yy;   
          if(p<=n)and(q<=m) then a[p,q]:=-1;   
        end;   
        a[-1,0]:=-1;a[0,-1]:=-1;   
        a[n,m]:=1;   
      end;   
    procedure main;   
      var  
        i,j:integer;   
      begin  
        for i:=n downto 0 do  
          for j:=m downto 0 do begin  
            if (a[i,j]<>-1)and(a[i-1,j]<>-1)then inc(a[i-1,j],a[i,j]);   
            if (a[i,j]<>-1)and(a[i,j-1]<>-1)then inc(a[i,j-1],a[i,j]);   
          end;   
  
      end;   
  begin  
    ini;   
    main;   
    writeln(f2,a[0,0]);   
    close(f2);   
  end.