[暑假集训--数位dp]hdu5787 K-wolf Number

Alice thinks an integer x is a K-wolf number, if every K adjacent digits in decimal representation of x is pairwised different.
Given (L,R,K), please count how many K-wolf numbers in range of L,RL,R

.

Input

The input contains multiple test cases. There are about 10 test cases.

Each test case contains three integers L, R and K.

1≤L≤R≤1e18
2≤K≤52≤K≤5

Output

For each test case output a line contains an integer.

Sample Input

1 1 2
20 100 5

Sample Output

1
72

问有多少个数，任意连续k位都不相同

记一下前k-1位，有没有前导零

 #include<cstdio>
 #include<iostream>
 #include<cstring>
 #include<cstdlib>
 #include<algorithm>
 #include<cmath>
 #include<queue>
 #include<deque>
 #include<set>
 #include<map>
 #include<ctime>
 #define LL long long
 #define inf 0x7ffffff
 #define pa pair<int,int>
 #define mkp(a,b) make_pair(a,b)
 #define pi 3.1415926535897932384626433832795028841971
 using namespace std;
 inline LL read()
 {
     LL x=,f=;char ch=getchar();
     while(ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}
     while(ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}
     return x*f;
 }
 LL n,len,l,r,k;
 LL f[][][];
 int zhan[];
 int d[];
 inline LL dfs(int now,int stat,int lead,int fp)
 {
     if (now==)return ;
     if (!fp&&f[now][stat][lead]!=-)return f[now][stat][lead];
     LL ans=,mx=fp?d[now-]:;
     int lst=;
     for(int i=now;i<=min(now+k-,len);i++)if (zhan[i]!=-)lst|=<<zhan[i];
     for (int i=;i<=mx;i++)
     {
         if (lst&(<<i))continue;
         if (i==&&lead&&now-!=)zhan[now-]=-;else zhan[now-]=i;
         if (zhan[now-]!=-)lst|=(<<i);
         ans+=dfs(now-,lst,lead&&i==&&now-!=,fp&&(i==d[now-]));
         if (zhan[now-]!=-)lst-=(<<i);
     }
     if (!fp)f[now][stat][lead]=ans;
     return ans;
 }
 inline LL calc(LL x)
 {
     if (!x)return ;
     LL xxx=x;
     len=;
     while (xxx)
     {
         d[++len]=xxx%;
         xxx/=;
     }
     LL sum=;
     for (int i=;i<=d[len];i++)
     {
         if (i==&&len!=)zhan[len]=-;else zhan[len]=i;
         if (zhan[len]!=-)sum+=dfs(len,<<zhan[len],zhan[len]==-,i==d[len]);
         else sum+=dfs(len,,zhan[len]==-,i==d[len]);
         zhan[len]=-;
     }
     return sum;
 }
 main()
 {
     while (~scanf("%lld%lld%lld",&l,&r,&k))
     {
         memset(f,-,sizeof(f));
         printf("%lld\n",calc(r)-calc(l-));
     }
 }

hdu 5787