bellman-ford.txt

bellman-ford的模板

 
 
 
 const htm:array [1..4,1..2] of integer=((0,1),(1,0),(1,-0),(0,-1));
var q,w,e,r,m1,m2,m3,m4,hang,lie,result,x1,y1:integer;
    map:array [0..101,0..101] of byte;
    been:array [0..101,0..101]  of boolean;
    in1,out1:text;
procedure search(x,y:integer);
var q1:integer;
begin
  if ((x<>hang)  or (y<>lie)) and (result=0) then
   begin
     for q1:=1 to 4 do
      begin
       x1:=x+htm[q1,1];
       y1:=y+htm[q1,2];
        if (not been[x1,y1]) and
           (map[x1,y1]=1) and
           (x1>0) and
           (y1>0) and
           (x1<=hang) and
           (y1<=lie)  then
           begin
            been[x1,y1]:=true;
            search(x1,y1);
            been[x1,y1]:=false;
           end;
      end;
   end
    else
     result:=1;
end;
begin
assign(in1,'a.in');
reset(in1);
assign(out1,'a.out');
rewrite(out1);
readln(in1,hang,lie);
for q:=1 to hang do
 for w:=1 to lie do
   read(in1,map[q,w]);
search(1,1);
 if result=1 then
  writeln(out1,'Yes')
   else
    writeln(out1,'No');
close(out1);
end.