UVa 11361 - Investigating Div-Sum Property

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=2346

数位DP

代码：

#include <iostream>

#include <cstdio>

#include <string>

#include <cstring>

#include <cmath>

#include <algorithm>

#include <queue>



#define ll long long

using namespace std;



int dp[11][90][10002];

int a[11];

int c[11];

int M;

int dfs(int x,int k1,int k2,int flag)

{

    if(x==-1)

    {

        if(k1==0&&k2==0)

        return 1;

        else

        return 0;

    }

    if(!flag&&dp[x][k1][k2]!=-1)

    return dp[x][k1][k2];

    int up=(flag)?a[x]:9;

    int sum=0;

    for(int i=0;i<=up;++i)

    {

        //sum+=dfs(x-1,(k1+i)%M,(k2*10+i)%M,flag&&(i==up));



        if(((k1-i)%M+M)%M<90)//两种递归，代表两种不同的含义，都是正确的

        sum+=dfs(x-1,((k1-i)%M+M)%M,((k2-i*c[x])%M+M)%M,flag&&(i==up));
    }

    if(!flag)

    dp[x][k1][k2]=sum;



    return sum;

}

int solve(int k)

{

    int len=0;

    while(k)

    {

        a[len++]=k%10;

        k=k/10;

    }

    return dfs(len-1,0,0,1);

}

int main()

{

    //freopen("data.in","r",stdin);

    int T;

    cin>>T;

    while(T--)

    {

        memset(dp,-1,sizeof(dp));

        int a,b;

        cin>>a>>b>>M;

        c[0]=1;

        for(int i=1;i<=10;++i)

        c[i]=(c[i-1]*10)%M;

        //cout<<b<<" "<<solve(b)<<endl;

        cout<<solve(b)-solve(a-1)<<endl;

    }

    return 0;

}