hdu 3652 B-number 数位dp

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define pb(x) push_back(x)
 4 #define ll long long
 5 #define mk(x, y) make_pair(x, y)
 6 #define lson l, m, rt<<1
 7 #define mem(a) memset(a, 0, sizeof(a))
 8 #define rson m+1, r, rt<<1|1
 9 #define mem1(a) memset(a, -1, sizeof(a))
10 #define mem2(a) memset(a, 0x3f, sizeof(a))
11 #define rep(i, a, n) for(int i = a; i<n; i++)
12 #define ull unsigned long long
13 typedef pair<int, int> pll;
14 const double PI = acos(-1.0);
15 const double eps = 1e-8;
16 const int mod = 1e9+7;
17 const int inf = 1061109567;
18 const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
19 int dp[20][30][2][10], digit[20];
20 int dfs(int len, int num, int pre, bool ok, bool fp) {
21     if(!len) {
22         return ok&&num==0;
23     }
24     if(!fp&&dp[len][num][ok][pre]!=-1)
25         return dp[len][num][ok][pre];
26     int maxx = fp?digit[len]:9, ret = 0;
27     for(int i = 0; i<=maxx; i++) {
28         ret += dfs(len-1, (num*10+i)%13, i, ok||(pre==1&&i==3), fp&&i==maxx);
29     }
30     if(!fp)
31         return dp[len][num][ok][pre] = ret;
32     return ret;
33 }
34 int cal(int n) {
35     int len = 0;
36     while(n) {
37         digit[++len] = n%10;
38         n/=10;
39     }
40     return dfs(len, 0, 0, 0, 1);
41 }
42 int main()
43 {
44     int a;
45     mem1(dp);
46     while(scanf("%d", &a)!=EOF) {
47         printf("%d\n", cal(a));
48     }
49 }