【leetcode】1316. Distinct Echo Substrings

Topics are as follows:

Return the number of distinct non-empty substrings of text that can be written as the concatenation of some string with itself.

Example 1:

Input: text = "abcabcabc"
Output: 3
Explanation: The 3 substrings are "abcabc", "bcabca" and "cabcab".

Example 2:

Input: text = "leetcodeleetcode"
Output: 2
Explanation: The 2 substrings are "ee" and "leetcodeleetcode".

Constraints:

• 1 <= text.length <= 2000
• text has only lowercase English letters.

Problem-solving ideas: This title is really wonderful, I thought it was to find out in line with (xxx) * substring such formats n, did not think it was (xxx) * 2 format, which means that, into a string two front portions, two values are the same part. Because text.length <= 2000, so direct violence calculate it.

code show as below:

class Solution(object):
    def distinctEchoSubstrings(self, text):
        """
        :type text: str
        :rtype: int
        """
        res = 0
        dic = {}
        # dp = [[0]* len(text) for _ in text]
        for i in range(len(text)):
            for j in range(i + 1, len(text)):
                if (j - i + 1) % 2 != 0:
                    continue
                mid = (i+j) / 2
                #print text[i:mid],text[mid:j+1]
                v1 = text[i:mid+1]
                v2 = text[mid+1:j+1]
                if v1 == v2 and v1 not in dic:
                    #print v1,v2
                    res += 1
                    dic[v1] = 1
        return res