codevs 3732 解方程

神题不可言会。

f(x+p)=f(x)(mod p)

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxl 10050
#define maxn 105
using namespace std;
int n,m,num[maxn][maxl],prime[]={,,,,,},a[maxn],flag[maxn],ans[maxl*],cnt=;
char s[maxl];
bool vis[][];
void solve(int x)
{
    for (int i=;i<=n;i++)
    {
        int data=;
        for (int j=;j<=num[i][];j++)
            data=(data*+num[i][j])%prime[x];
        a[i]=data;
        if (flag[i]) a[i]=-a[i];
    }
    vis[x][]=true;
    for (int i=;i<=prime[x]-;i++)
    {
        int data=a[n]*i%prime[x];
        for (int j=n-;j>=;j--)
            data=(data+a[j])*i%prime[x];
        if (data==) vis[x][i]=true;
    }
}
int main()
{
    memset(flag,false,sizeof(flag));
    scanf("%d%d",&n,&m);
    for (int i=;i<=n;i++)
    {
        scanf("%s",s);
        if (s[]=='-')
        {
            flag[i]=true;
            int len=strlen(s);num[i][]=len-;
            for (int j=;j<=len-;j++)
                num[i][j]=s[j]-'';
        }
        else
        {
            int len=strlen(s);num[i][]=len;
            for (int j=;j<=len-;j++)
                num[i][j+]=s[j]-'';
        }
    }
    for (int i=;i<=;i++)
        solve(i);
    for (int i=;i<=m;i++)
    {
        bool now=true;
        for (int j=;j<=;j++)
            now&=vis[j][i%prime[j]];
        if (now) ans[++cnt]=i;
    }
    printf("%d\n",cnt);
    for (int i=;i<=cnt;i++)
        printf("%d\n",ans[i]);
    return ;
}