hdu 4722 Good Numbers 数位DP

数位DP！！！

代码如下：

 

 1 #include<iostream>

 2 #include<stdio.h>

 3 #include<algorithm>

 4 #include<iomanip>

 5 #include<cmath>

 6 #include<cstring>

 7 #include<vector>

 8 #define ll __int64

 9 #define pi acos(-1.0)

10 #define MAX 50000

11 using namespace std;

12 ll dp[22][15][200];

13 int bit[22];

14 ll dfs(int pos,int mod,int sum,bool f)

15 {

16     if(pos==-1) return mod==0;

17     if(!f&&dp[pos][mod][sum]!=-1) return dp[pos][mod][sum];

18     ll ans=0;

19     int e=f?bit[pos]:9;

20     for(int i=0;i<=e;i++){

21         ans+=dfs(pos-1,(mod+i)%10,sum+i,f&&i==e);

22     }

23     if(!f) dp[pos][mod][sum]=ans;

24     return ans;

25 }

26 ll solve(ll n)

27 {

28     int m=0;

29     while(n){

30         bit[m++]=n%10;

31         n/=10;

32     }

33     return dfs(m-1,0,0,1);

34 }

35 int main(){

36     int t,ca=0;

37     ll a,b;

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

39     scanf("%d",&t);

40     while(t--){

41         scanf("%I64d%I64d",&a,&b);

42         if(a>b) swap(a,b);

43         printf("Case #%d: %I64d\n",++ca,solve(b)-solve(a-1));

44     }

45     return 0;

46 }

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