Codeforces Round #785 (Div. 2) C. Palindrome Basis

思路：我们很容易想到先筛去回文数，然后就变成完全背包求方案数裸题了

#include<vector>
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main()
{
    vector<int> dp(40009,0);
    vector<int> hw;
    for(int i=1;i<=40000;i++){
        string s=to_string(i);
        string t=s;
        reverse(t.begin(),t.end());
        if(s==t) hw.push_back(i);
    }
    dp[0]=1;
    int len=hw.size();
    for(int i=0;i<len;i++){
        int v=hw[i];
        for(int j=v;j<=40000;j++){
            dp[j]=(dp[j]+dp[j-v])%1000000007;
        }
    }
    int time;cin>>time;
    while(time--){
        int temp;cin>>temp;
        cout<<dp[temp]<<endl;
    }
}