windy数(简单数位DP)

 1 #include<stdio.h>
 2 #include<math.h>
 3 #include<stdlib.h>
 4 #include<string.h>
 5 
 6 int dp[15][15];
 7 
 8 void Init()
 9 {
10     memset(dp,0,sizeof(dp));
11     int i,j,k;
12     for (i=0;i<10;i++)
13     dp[1][i]=1;
14     
15     for (i=2;i<=10;i++)
16     {
17         for (j=0;j<10;j++)
18         {
19             for (k=0;k<10;k++)
20             if (abs(j-k)>=2)
21             dp[i][j]+=dp[i-1][k];
22         }
23     }
24 }
25 
26 
27 int slove(int x)
28 {
29     int len=0;
30     int w[15];
31     while (x)
32     {
33         w[++len]=x%10;
34         x/=10;
35     }
36     w[len+1]=0;
37     int ans=0;
38     int i,j;
39     for (i=1;i<len;i++)
40     for (j=1;j<10;j++)
41     ans+=dp[i][j];
42     
43     for (i=1;i<w[len];i++)
44     ans+=dp[len][i];
45     
46     for (i=len-1;i;i--)
47     {
48         for (j=0;j<w[i];j++)
49         {
50             if (abs(w[i+1]-j)>=2)
51             ans+=dp[i][j];
52         }
53         if (abs(w[i+1]-w[i])<2)
54         break;
55     }
56     return ans;
57 }
58 
59 int main()
60 {
61     Init();
62     int l,r;
63     while (scanf("%d%d",&l,&r)!=EOF)
64     {
65         printf("%d\n",slove(r+1)-slove(l));
66     }
67     return 0;
68 }