第七周 Leetcode 466. Count The Repetitions 倍增DP (HARD)

const int maxn=100+1,INF=1e+9;


long long int dp[maxn][30];

class Solution {
public:
    int getMaxRepetitions(string s1, int n1, string s2, int n2) {
    	memset(dp,0,sizeof(dp));
        int len1=s1.length(),len2=s2.length();
        int l1=0,l2=0;
        for(int i=0;i<len1;i++)
        	{
        	 l1=i;l2=0;
        	 while(l2<len2)
        	 	{
			 
        	 	 while(l1<n1*len1&&s1[l1%len1]!=s2[l2])l1++;
        	 	 l1++;l2++;
        		}
        	 dp[i][0]=l1-i;
			}
		for(int k=1;k<30;k++)
			for(int i=0;i<len1;i++)
				{
				 dp[i][k]=dp[i][k-1]+dp[(i+dp[i][k-1])%len1][k-1];
				}
		long long int ans=0;
		int begin=0;
		for(int k=29;k>=0;k--)
			 while((begin+dp[(begin%len1)][k])<=n1*len1)
			 		{ans+=(1<<k);begin+=dp[(begin%len1)][k];}
		return ans/n2;
			
    }
};