HYSBZ 1616（纯深搜）

题目大意：一张图G，有一些障碍物，求路径长度一定（可环）时的路径总数

果断广搜

Program ttd;
var
   n,m,t,i,j,k,x1,x2,y1,y2:longint;
   s:string;
   b:array[0..101,0..101] of boolean;

   f:array[0..15,0..101,0..101] of longint;
begin
   readln(n,m,t);
   fillchar(b,sizeof(b),true);
   for i:=1 to n do
   begin
      readln(s);
      for j:=1 to m do if s[j]='*' then b[i,j]:=false;
   end;
   readln(x1,y1,x2,y2);
   fillchar(f,sizeof(f),0);
   f[0,x1,y1]:=1;

   for k:=1 to t do
   begin
      for i:=1 to n do
         for j:=1 to m do
            if f[k-1,i,j]>0 then
            begin
               if b[i+1,j] then inc(f[k,i+1,j],f[k-1,i,j]);
               if b[i-1,j] then inc(f[k,i-1,j],f[k-1,i,j]);
               if b[i,j+1] then inc(f[k,i,j+1],f[k-1,i,j]);
               if b[i,j-1] then inc(f[k,i,j-1],f[k-1,i,j]);



            end;


   end;
             {
   for k:=0 to t do
   begin
   for i:=1 to n do
   begin
      for j:=1 to m do
      begin
         write(f[k,i,j],' ');
      end;
      writeln;
      end;
      writeln;
   end;
            }
   writeln(f[t,x2,y2]);


end.