Codeforces 414B Mashmokh and ACM (DP)
Mashmokh's boss, Bimokh, didn't like Mashmokh. so he fired him. mashmokh decided to go to university and participant ipate in ACM instead of finding a new job. he wants to become a member of Bamokh's team. in order to join he was given some programming tasks and one week to solve them. mashmokh is not a very experienced programmer. actually he is not a programmer at all. so he wasn' t able to solve them. that's why he asked you to help him with these tasks. one of these tasks is the following.
A sequenceLIntegersB1 ,?B2 ,?...,?BL(1? ≤?B1? ≤?B2? ≤ ?...? ≤?BL? ≤?N) Is called good if each number divides (without a remainder) by the next number in the sequence. More formally for allI(1? ≤?I? ≤?L? -? 1 ).
GivenNAndKFind the number of good sequences of lengthK. As the answer can be rather large print it modulo 1000000007 (109? +? 7 ).
Input
The first line of input contains two space-separated integersN,?K(1? ≤?N,?K? ≤? 2000 ).
Output
Output a single integer-the number of good sequences of lengthKModulo 1000000007 (109? +? 7 ).
Sample test (s) input
3 2
Output
5
Input
6 4
Output
39
Input
2 1
Output
2
Note
In the first sample the good sequences are: [1 ,? 1],? [2 ,? 2],? [3 ,? 3],? [1 ,? 2],? [1 ,? 3].
The question is the DP about the counting problem. If dp [I] [j] is set, it indicates the number of solutions whose end length is j with I: dp [I] [j] = sum (dp [k] [J-1]) (I % k = 0) Special dp [I] [1] = 1;
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using namespace std;#define REPF( i , a , b ) for ( int i = a ; i <= b ; ++ i )#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )#define CLEAR( a , x ) memset ( a , x , sizeof a )typedef long long LL;typedef pair
pil;const int INF = 0x3f3f3f3f;const int MOD=1e9+7;const int maxn=2000+100;LL dp[maxn][maxn];int n,k;int main(){ while(cin>>n>>k) { CLEAR(dp,0); REPF(i,1,n) dp[i][1]=1; for(int j=1;j<=n;j++) for(int kk=j;kk<=n;kk+=j) for(int i=2;i<=k;i++) dp[kk][i]=(dp[kk][i]+dp[j][i-1])%MOD; LL ans=0; REPF(i,1,n) ans=(ans+dp[i][k])%MOD;