Related Topics: “字符串”: https://leetcode.com/tag/string/ “字符串匹配”: https://leetcode.com/tag/string-matching/ Similar Questions: “实现 strStr()”: https://leetcode.com/problems/implement-strstr/ “重复叠加字符串匹配”: https://leetcode.com/problems/repeated-string-match/

Problem: Link to heading

给定一个非空的字符串，判断它是否可以由它的一个子串重复多次构成。给定的字符串只含有小写英文字母，并且长度不超过10000。

示例 1:

输入: "abab"

输出: True

解释: 可由子字符串 "ab" 重复两次构成。

示例 2:

输入: "aba"

输出: False

示例 3:

输入: "abcabcabcabc"

输出: True

解释: 可由子字符串 "abc" 重复四次构成。 (或者子字符串 "abcabc" 重复两次构成。)

Solution: Link to heading

https://leetcode-cn.com/problems/repeated-substring-pattern/solution/zhong-fu-de-zi-zi-fu-chuan-by-leetcode-solution/

class Solution {
public:
    void getNext (int* next, const string& s){
        next[0] = -1;
        int j = -1;
        for(int i = 1;i < s.size(); i++){
            while(j >= 0 && s[i] != s[j+1]) {
                j = next[j];
            }
            if(s[i] == s[j+1]) {
                j++;
            }
            next[i] = j;
        }
    }
    bool repeatedSubstringPattern (string s) {
        if (s.size() == 0) {
            return false;
        }
        int next[s.size()];
        getNext(next, s);
        int len = s.size();
        if (next[len - 1] != -1 && len % (len - (next[len - 1] + 1)) == 0) {
            return true;
        }
        return false;
    }
};