p1121m.pas

来自「www.vijos.cn上一些习题的参考源码」· PAS 代码 · 共 97 行

program p1121m;
const
    MAXN=15;
    MAXM=15;
    ma:array[1..8,1..2] of integer=((-2,1),(-1,2),(1,2),(2,1),(-2,-1),(-1,-2),(1,-2),(2,-1));
var
    can:array[0..MAXN,0..MAXM] of boolean;
    num:array[0..MAXN,0..MAXM] of longint;
    n,m,mx,my:integer;
    i,j,d,x,y,k:integer;
    {fout:text;}

function bound(x,y:integer):boolean;
begin
    if (x>=0) and (x<=n) and (y>=0) and (y<=m) then bound:=true
    else bound:=false;
end;

procedure init;
begin
    fillchar(num,sizeof(num),0);
    fillchar(can,sizeof(can),true);
    can[mx,my]:=false;  {注意：不要忘了马所在的点}
    for i:=1 to 8 do
        if bound(mx+ma[i,1],my+ma[i,2]) then
            can[mx+ma[i,1],my+ma[i,2]]:=false;
end;

procedure move(k:integer; var x,y:integer);
begin
    case k of
        1:inc(x);
        2:inc(y);
    end;
end;



begin
    readln(n,m,mx,my);
    
    init;
    
    num[0,0]:=1;
    {num[0,1]:=1;
    num[1,0]:=1;}
    
    for i:=0 to n do begin
        for j:=0 to m do begin
            if not can[i,j] then continue;
            for k:=1 to 2 do begin
                x:=i; y:=j;
                move(k,x,y);
                if can[x,y] and bound(x,y) then
                    inc(num[x,y],num[i,j]);
            end;
        end;
    end;
    
    {for d:=0 to n do begin
    for i:=0 to d do begin
        j:=d-i;
        if not can[i,j] then continue;
        for k:=1 to 2 do begin
            x:=i; y:=j;
            move(k,x,y);
            if can[x,y] and bound(x,y) then
                inc(num[x,y],num[i,j]);
        end;
    end;
    end;
    
    for d:=n+1 to 2*n do begin
        for i:=1 to n do begin
            j:=d-i;
            if not can[i,j] then continue;
            for k:=1 to 2 do begin
                x:=i; y:=j;
                move(k,x,y);
                if can[x,y] and bound(x,y) then
                    inc(num[x,y],num[i,j]);
            end;
        end;
    end;}
    
    writeln(num[n,m]);
    
    {assign(fout,'t1.out'); rewrite(fout);
    for i:=0 to n do begin
        for j:=0 to n do begin
            write(fout,num[i,j]:3);
        end;
        writeln(fout);
    end;
    close(fout);}
end.