459. Repeated Substring Pattern

459. Repeated Substring Pattern

• 题目描述：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: TrueExplanation: It's the substring "ab" twice.

• Example 2:

  Input: "aba"Output: False

• Example 3:

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

• 思路：见代码

• 代码

  package String;/*** @Author OovEver* @Date 2017/12/4 17:06*/public class LeetCode459 {  public  boolean repeatedSubstringPattern(String s) {      int len = s.length();      for(int i=len/2;i>0;i--) {//            只有len%i==0才代表当前的i个元素可以重复的组成s字符          if (len % i == 0) {              String subS = s.substring(0, i);//                假设可以组成s字符，需要m个长度为i的子字符串              int m = len / i;              int j;              for(j=1;j<m;j++) {//                    0到i的字符与i * j到 i * j + i不相等                  if (!subS.equals(s.substring(i * j, i * j + i))) {                      break;                  }              }              if (j == m) {                  return true;              }          }      }      return false;  }}