Translation between different Positional notations 负进制转换 NOIP 2000-1

2007050301.pas

//https://joeyaochou.wordpress.com/2015/01/23/translation-between-different-positional-notations-%E8%B4%9F%E8%BF%9B%E5%88%B6%E8%BD%AC%E6%8D%A2-noip-2000-1/
const
     maxn=50;{数组限制}
     ch:string[20]='0123456789ABCDEFGHIJ';{A=10 B=11 ...}

var
     i,j,n,m,k:longint;
     bit:array[0..maxn] of longint;
     {纪录每一位的 纯数值(A B...暂用数值表示)}
begin
     while not eof(input) do
     begin
       readln(n,m);
       i:=0; k:=n;
       while (k<0)or(k>=-m) do
       {如果0<k<-m,那么该十进制数字直接是m进制数当位数字}
       begin
         bit[i]:=k mod m;{求m进制数的第i位数值}
         k:=k div m;
         if bit[i]<0 then
         begin
           bit[i]:=bit[i]-m;{该位数值不足0...}
           k:=k+1;{...从上一位借位}
         end;
         inc(i);
       end;
       bit[i]:=k;
       for j:=i downto 0 do
         write(ch[bit[j]+1]);
         {将每一位的数值转换成符号 1=1 2=2 .. A=10 B=11..}
       writeln;
     end;
end.