xiaozqh

[srcbox.git] / domino.pas

var
        a,b,f,g:array [0..1000] of longint;
        i,j,n:longint;
        
begin 
        readln(n);
        for i:=1 to n do begin readln(a[i],b[i]); inc(f[1],a[i]-b[i]); g[i]:=maxlongint; end;
        for i:=2 to n do 
                begin
                        for j:=1 to i-1 do 
                                if abs(f[j]+2*(b[i]-a[i]))<f[i] then begin f[i]:=f[j]+2*(b[i]-a[i]); g[i]:=g[j]+1; end 
                                        else 
                                                if (g[j]<g[i]) then begin f[i]:=f[j]; g[i]:=g[j]; end;
                end;
        writeln(g[n]);
        close(input); close(output);
end.