/**
knakul853
**/
class Solution {
public:
    bool repeatedSubstringPattern(string s) {

        int n = (int)s.size();
        vector<int>dp(n, 0);

         for(int i=1;i<n;i++)
         {
             int j = dp[i-1];

             while(j>=1 && s[i] != s[j] )j = dp[j-1];

             if(s[i] == s[j])
             {
                 j++;
             }

             dp[i] = j;
         }

        return dp[n-1] && dp[n-1] % (n - dp[n-1]) == 0;

    }
};