洛谷 P1303 A*B Problem
題目描述
求兩數的積。

分析
高精乘

var
 s1,s2:ansistring;
 a,b,c:array[0..100000]of longint;
 i,j:longint;
begin
  readln(s1);
  readln(s2);
  a[0]:=length(s1);
  b[0]:=length(s2);
  for i:=a[0] downto 1 do val(s1[i],a[a[0]-i+1]);
  for i:=b[0] downto 1 do val(s2[i],b[b[0]-i+1]);
  for i:=1 to a[0] do
   for
 
 j:=1 to b[0] do
    begin
      c[i+j-1]:=a[i]*b[j]+c[i+j-1];
      c[i+j]:=c[i+j]+c[i+j-1]div 10;
      c[i+j-1]:=c[i+j-1]mod 10;
    end;
  if ((s1[1]='-')or(s2[1]='-'))and((s1[1]<>'-')or(s2[1]<>'-'))and(c[i+j-1]<>0)then write('-');
  c[0]:=a[0]+b[0];
  for i:=a[0]+b[0] downto 2 do if c[i]=0
 
 then dec(c[0]) else break;
  for i:=c[0] downto 1 do write(c[i]);
end.