Given a non-empty string check if it can be constructed by taking a substring of it and appending multiple copies of the substring together. You may assume the given string consists of lowercase English letters only and its length will not exceed 10000.

 

Example 1:

Input: "abab"
Output: True
Explanation: It's the substring "ab" twice.

Example 2:

Input: "aba"
Output: False

Example 3:

Input: "abcabcabcabc"
Output: True
Explanation: It's the substring "abc" four times. (And the substring "abcabc" twice.)

class Solution {
    public boolean repeatedSubstringPattern(String s) {
        int n = s.length();
        StringBuilder sb = new StringBuilder();
        for(int i = 1; i <= n / 2; i++) {
            if(n % i == 0) {
                int times = n / i;
                String cur = s.substring(0, i);
                sb = new StringBuilder();
                for(int j = 0; j < times; j++) sb.append(cur);
                //System.out.println(sb.toString());
                if(s.equals(sb.toString())) return true;
            }
        }
        return false;
    }
}

string是否能拆分成n * substring，拆分即可，simulation