hdu 4447 Yuanfang, What Do You Think?

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<cstring>
#define MAX 1102
using namespace std;
struct pol
{
int bit[MAX],len;
void init(){memset(bit,0,sizeof(bit));len=1;}
}p[MAX];
int ans[MAX];
int com(pol a,pol b)
{
if(a.len!=b.len)return a.len-b.len;
for(int i=a.len-1;i>=0;i--)
if(a.bit[i]!=b.bit[i]){
if(abs(a.bit[i])!=abs(b.bit[i]))
return abs(a.bit[i])-abs(b.bit[i]);
return a.bit[i]-b.bit[i];
}
return 0;
}
bool cmp(int a,int b)
{
return com(p[a],p[b])<0;
}
void shows(int n)
{
if(n>1) printf("x^%d",n);
else if(n==1) printf("x");
}
void show(pol a)
{
int x;
printf("(");
for(int i=a.len-1;i>=0;i--){
if(a.bit[i]==0) continue;
if(i==0){
if(a.bit[i]>0) printf("+%d",a.bit[i]);
else printf("%d",a.bit[i]);
continue;
}
if(i==a.len-1){
if(a.bit[i]<0) printf("-");
x=abs(a.bit[i]);
if(x>1) printf("%d",x);
shows(i);
continue;
}
if(a.bit[i]<0) printf("-");
else printf("+");
x=abs(a.bit[i]);
if(x>1) printf("%d",x);
shows(i);
}
printf(")");
}
pol Div(pol a,pol b)
{
pol c;
c.init();
for(int i=a.len-1;i>=0;i--)
if(a.bit[i]){
c.bit[i-b.len+1]=a.bit[i];
int cnt=0,cur=a.bit[i];
for(int j=b.len-1;j>=0;j--){
a.bit[i-cnt]-=cur*b.bit[j];
cnt++;
}
}
c.len=a.len;
while(c.len>1&&c.bit[c.len-1]==0) c.len--;
return c;
}
int main(){
p[1].bit[0]=-1;
p[1].bit[1]=1;
p[1].len=2;
for(int i=2;i<MAX;i++){
p[i].init();
p[i].bit[i]=1;p[i].bit[0]=-1;
p[i].len=i+1;
p[i]=Div(p[i],p[1]);
for(int j=2;j*j<=i;j++){
if(i%j==0){
p[i]=Div(p[i],p[j]);
if(j*j!=i) p[i]=Div(p[i],p[i/j]);
}
}
}
int n,m;
while(scanf("%d",&n)&&n){
if(n==1){
puts("x-1");
continue;
}
m=0;
for(int i=1;i*i<=n;i++){
if(n%i==0){
ans[m++]=i;
if(i*i!=n) ans[m++]=n/i;
}
}
sort(ans,ans+m,cmp);
for(int i=0;i<m;i++)
show(p[ans[i]]);
printf("\n");
}
return 0;
}