PKU2603 brave ballonists

这道题的大意是，十个数相乘，求所得积的约数个数。但是，它考察的显然不是高精度计算，而是约数个数定理。对于一个数a，如果我们有：

a=(p1^k1)* (p2^k2)* (p3^k3)*……*(pn^kn)

       那么a的约数个数为（k1+1）*（k2+1）*（k3+1）*……*（kn+1）

program Brave_balloonists; const maxn=15000; var p:array[0..maxn] of boolean; s,list:array[0..maxn] of longint; tot,ans:longint; procedure prework; begin ans:=1; fillchar(p,sizeof(p),1); fillchar(s,sizeof(s),0); end; procedure makeprime; var i,j:longint; begin for i:=2 to trunc(sqrt(maxn)) do if p[i] then begin j:=i*i; while j<=maxn do begin p[j]:=false; inc(j,i); end; end; for i:=2 to maxn do if p[i] then begin inc(tot); list[tot]:=i; inc(s[tot]); end; end; procedure init; var i,w,k:longint; begin for i:=1 to 10 do begin readln(w); k:=1; while w<>1 do begin while w mod list[k]=0 do begin inc(s[k]); w:=w div list[k]; end; inc(k); end; end; end; procedure outit; var i:longint; begin for i:=1 to tot do ans:=ans*s[i] mod 10; writeln(ans); end; begin assign(input,'a.in'); reset(input); assign(output,'a.out'); rewrite(output); prework; makeprime; init; outit; close(input); close(output); end.