POJ 2390 (小数高精度乘法）

小数高精度乘法

m*(1+r/100)^y

Program P2390;const   maxn=40000;   F=10;type   arr=record       d:array[1..maxn] of longint;       len,doc:longint;       end;var   r,m:arr;   y:longint;   i:longint;   a,b:arr;function max(a,b:longint):longint;begin   if a<b then exit(b) else exit(a);end;procedure multipy(a,b:arr;var c:arr);var   i,j,len:longint;begin   fillchar(c,sizeof(c),0);   c.len:=a.len+b.len;   for i:=1 to a.len do      for j:=1 to b.len do      begin         inc(c.d[i+j-1],a.d[i]*b.d[j]);         inc(c.d[i+j],c.d[i+j-1] div F);         c.d[i+j-1]:=c.d[i+j-1] mod F;      end;   while (c.d[c.len]=0) and (c.len>1) do dec(c.len);   c.doc:=a.doc+b.doc;end;procedure to_arr(doc:longint;var c:arr);var   x,i,n:longint;begin   read(x);   i:=0;   while (x>0) do   begin      inc(i);      c.d[i]:=x mod F;      x:=x div F;   end;   c.len:=i;   c.doc:=doc;end;Procedure jie(a:arr;x:longint;var c:arr);begin   if x=1 then begin c:=a; exit; end;   fillchar(c,sizeof(c),0);   if (x mod 2=0) then   begin      jie(a,x div 2,c);      multipy(c,c,c);   end   else   begin      jie(a,x div 2,c);      multipy(c,c,c);      multipy(a,c,c);   end;end;begin   to_arr(2,r);   r.len:=3;r.d[3]:=1;   to_arr(0,m);   read(y);   jie(r,y,r);   multipy(m,r,m);   for i:=m.len downto m.doc+1 do write(m.d[i]);   writeln;end.