Leetcode 459. Repeated Substring Pattern

1 解题思想

题目的意思，就是对于给定的数组，问是否包含一个子串，子串重复N次（N>1)后可以得到原串

我这里没有用什么太高级的算法。。

直接每次选择一个可以被整除的较小的数，截取开头的那几个字符，然后重复到原长度验证就好。。比较蠢。。懒得写了

2 原题

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

3 AC解

public class Solution {
    /*直接截取了重复试验就好*/
    public boolean repeatedSubstringPattern(String str) {
        int n = str.length();
        for(int i=n/2;i>=1;i--) {
            if(n%i==0) {
                int m = n/i;
                String substring = str.substring(0,i);
                StringBuilder sb = new StringBuilder();
                for(int j=0;jif(sb.toString().equals(str)) return true;
            }
        }
        return false;

    }
}