1.[SCOI2009] windy 數

模板題

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 inline int read()
 4 {
 5     int x=0;char c=getchar();
 6     for(;!isdigit(c);c=getchar());
 7     for(;isdigit(c);c=getchar()) x=x*10+c-'0';
 8     return x;
 9 } 
10 int a,b;
11 int dp[12][12],s[12];
12 inline int dfs(int
 
 now,int pre,int up,int oo)  
13 {
14     if(now==0) return 1;
15     if(!up&&dp[now][pre]!=-1) return dp[now][pre];
16     int maxn=up?s[now]:9;
17     int res=0;
18     for(int i=0;i<=maxn;i++)
19     {
20         if(abs(i-pre)<2) continue;
21         if(oo&&i==0) res+=dfs(now-1,-5
 
,0,1);
22         else res+=dfs(now-1,i,(up&&i==maxn),0);
23     }
24     if(!up&&!oo) dp[now][pre]=res; 
25     return res;
26 }
27 inline int part(int x)
28 {
29     int tot=0;
30     while(x)
31     {
32         s[++tot]=x%10;x/=10;
33     }
34     memset(dp,-1,sizeof(dp));
35     return
 
 dfs(tot,-5,1,1);
36 }
37 int main()
38 {
39     a=read();b=read();
40     printf("%d\n",part(b)-part(a-1));
41     return 0;
42 }