「NOIP2017模拟赛08.02」A**B

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题目链接：http://hhhoj.ngrok.cc/contest/3/problem/4

高精度乘法

小数点位数加一下就好了

注意前后的0以及输出规范

贴代码

 type arr=array[0..300]of longint; var s:string;     n,x,bo,i,j,t,len,bo1:longint;     ans,a:arr; function mul(a,b:arr):arr;  var i,j:longint;      var c:arr;   begin    fillchar(c,sizeof(c),0);    c[0]:=a[0]+b[0]-1;    for i:=1 to a[0] do     for j:=1 to b[0] do      begin       inc(c[i+j-1],a[i]*b[j]);       inc(c[i+j],c[i+j-1]div 10);       c[i+j-1]:=c[i+j-1]mod 10;      end;    if c[c[0]+1]>0 then inc(c[0]);    exit(c);   end;begin// assign(input,'1.in');reset(input);// assign(output,'1.out');rewrite(output); readln(s); if s[1]='.' then s:='0'+s; x:=pos(' ',s); bo:=0;val(copy(s,x+1,length(s)-x),n); for i:=1 to x-1 do if s[i]='.' then bo:=i; if bo<>0 then bo:=(x-1-bo)*n; while s[1]='0' do delete(s,1,1); len:=x-1; if s[1]='.' then delete(s,1,1); x:=pos(' ',s); len:=x-1;bo1:=0; for i:=1 to len do if s[i]='.' then bo1:=1; if bo1=1 then dec(len); i:=len;j:=1; a[0]:=len; while i>=1 do  begin   if s[j]='.' then inc(j);   a[i]:=ord(s[j])-48;   dec(i);inc(j);  end; ans[0]:=1;ans[1]:=1; for t:=1 to n do ans:=mul(ans,a); if bo>=ans[0] then begin                    write('.');                    for i:=1 to bo-ans[0] do write('0');                    for i:=ans[0] downto 1 do write(ans[i]);                   end               else begin                     for i:=1 to ans[0]-bo do write(ans[ans[0]-i+1]);                     if bo<>0 then write('.');                     for i:=ans[0]-i downto 1 do write(ans[i]);                    end; // close(input);close(output); end.

【写的有漏洞的，欢迎路过大神吐槽】

2017/08/02 22:03:29

Ending.

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