POJ1915 —— 双向广搜代码模板

Program poj1915;//By_Thispoet

Const

	maxn=100000;

	ddx:Array[1..8]of Integer=(1,1,2,2,-1,-1,-2,-2);

	ddy:Array[1..8]of Integer=(2,-2,1,-1,2,-2,1,-1);

Var

	i,j,k,m,n,p,q				:Longint;

	h,t							:Array[1..2]of Longint;

	step						:Array[1..2,0..300,0..300]of Longint;

	v							:Array[1..2,0..300,0..300]of Boolean;

	seq							:Array[1..2,1..maxn]of record x,y:Integer;end;

	flag						:Boolean;



Function Check(i,j:Longint):Boolean;

begin

	if (i>m)or(j>m)or(i<0)or(j<0)then exit(false);

	exit(true);

end;





Procedure Expand(code:Longint);

begin

	inc(h[code]);

	i:=seq[code,h[code]].x;

	j:=seq[code,h[code]].y;

	for k:=1 to 8 do

		begin

			p:=i+ddx[k];q:=j+ddy[k];

			if check(p,q) and not v[code,p,q] then

				begin

					inc(t[code]);

					seq[code,t[code]].x:=p;

					seq[code,t[code]].y:=q;

					v[code,p,q]:=true;

					step[code,p,q]:=step[code,i,j]+1;

					if v[1,p,q] and v[2,p,q] then

						begin

							flag:=true;

							exit;

						end;

				end;

		end;

end;





BEGIN



	readln(n);

	while n>0 do

		begin

			readln(m);dec(m);

			readln(p,q);

			fillchar(v,sizeof(v),0);

			fillchar(step,sizeof(step),0);

			seq[1,1].x:=p;seq[1,1].y:=q;

			v[1,p,q]:=true;

			readln(p,q);

			seq[2,1].x:=p;seq[2,1].y:=q;

			v[2,p,q]:=true;

			if v[1,p,q] and v[2,p,q] then

				begin

					writeln(0);

					dec(n);

					continue;

				end;

			h[1]:=0;h[2]:=0;

			t[1]:=1;t[2]:=1;

			flag:=false;

			repeat

				if (t[1]>h[1])and((t[1]-h[1]<t[2]-h[2])or(t[2]<=h[2]))then Expand(1) else

					if t[2]>h[2] then Expand(2);

				if flag then break;

			until (t[1]<=h[1])and(t[2]<=h[2]);

			if flag then writeln(step[1,p,q]+step[2,p,q]) else writeln(0);

			dec(n);

		end;



END.