Before bedtime little dp-codeforce414b-dp+ a little thought

Http://codeforces.com/problemset/problem/414/B

Define a string as a good string when this string conforms to the Di|di+1,1<i<k-1

Given an n is the range of the elements in the string, a k is the length of the string, calculating all possible counts of the string.

I started thinking about it. Dp[i][j] I represents the length of a string, and J represents the number of strings with a length of I ending with J.

But I think it's crooked. I'm thinking of introducing all I from i-1 so that each recursion has n^2 complexity.

Read the puzzle to understand is every time with I put i+1 launch.

#include <cstdio>#include<cstring>#include<algorithm>using namespacestd;Const intMOD =1000000007;intn,k,dp[ .][ .];intMain () { while(~SCANF ("%d%d",&n,&k)) {memset (DP,0,sizeofDP);  for(intI=1; i<=n;i++) dp[1][i] =1;  for(intI=1; i<k;i++)        {             for(intj=1; j<=n;j++)            {                 for(intp=j;p<=n;p+=j) {Dp[i+1][p] + = (dp[i][j]%MOD); Dp[i+1][P]%=MOD; }            }        }        intAns =0;  for(intI=1; i<=n;i++) {ans+=Dp[k][i]; Ans%=MOD; } printf ("%d\n", ans); }}

Before bedtime little dp-codeforce414b-dp+ a little thought