POJ2488 ——Dfs基础算法模板

Program poj2488;//By_Thispoet
Const 
	ddx:Array[1..8]of Integer=(-2,-2,-1,-1,1,1,2,2);
	ddy:Array[1..8]of Integer=(-1,1,-2,2,-2,2,-1,1);
	maxn=26;
Type
	rec=record
		ch:Char;
		num:Longint;
	end;
Var
	i,j,m,n,o,p,q			:Longint;
	v						:Array[1..maxn,1..maxn]of Boolean;
	stack					:Array[1..maxn*maxn]of rec;
	flag					:Boolean;
	
Procedure Printf();
begin
	for p:=1 to m*n do 
		write(stack[p].ch,stack[p].num);
	writeln;
end;
	
	
Function Check(i,j:Longint):Boolean;
begin
	if (i>n)or(i<=0)or(j>m)or(j<=0) then exit(false);
	exit(true);
end;
	
	
Procedure Dfs(code,i,j:Longint);
var k,p,q	:Longint;
begin
	if code=m*n then 
		begin
			Printf();
			flag:=true;
			exit;
		end;
	for k:=1 to 8 do 
		begin
			p:=i+ddx[k];q:=j+ddy[k];
			if check(p,q) and (not v[p,q]) then 
				begin	
					v[p,q]:=true;
					inc(code);
					stack[code].ch:=chr(p+64);
					stack[code].num:=q;
					Dfs(code,p,q);
					dec(code);
					if flag then exit;
					v[p,q]:=false;
				end;
		end;
end;
	
	
BEGIN

	readln(o);
	for q:=1 to o do 
		begin
			readln(m,n);
			writeln('Scenario #',q,':');
			flag:=false;
			fillchar(v,sizeof(v),0);
			for i:=1 to n do 
				begin
					for j:=1 to m do 
						begin
							stack[1].ch:=chr(i+64);
							stack[1].num:=j;
							v[i,j]:=true;
							Dfs(1,i,j);
							v[i,j]:=false;
							if flag then break;
						end;
					if flag then break;
				end;
			if not flag then 
				writeln('impossible');
			writeln;
		end;

END.