Leetcode 467. Unique Substrings in Wraparound String

Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd....".

Now we have another string p. Your job is to find out how many unique non-empty substrings of p are present in s. In particular, your input is the string p and you need to output the number of different non-empty substrings of p in the string s.

Note: p consists of only lowercase English letters and the size of p might be over 10000.

Example 1:

Input: "a"
Output: 1

Explanation: Only the substring "a" of string "a" is in the string  s.

Example 2:

Input: "cac"
Output: 2
Explanation: There are two substrings "a", "c" of string "cac" in the string s.

Example 3:

Input: "zab"
Output: 6
Explanation: There are six substrings "z", "a", "b", "za", "ab", "zab" of string "zab" in the string s.

Code (Java):

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

class Solution {     public int findSubstringInWraproundString(String p) {         if (p == null || p.length() == 0) {             return 0;         }                   int[] count = new int[26];         int ans = 0;         int maxLen = 1;         count[p.charAt(0) - 'a'] = 1;                   for (int i = 1; i < p.length(); i++) {             char curr = p.charAt(i);             char prev = p.charAt(i - 1);                           if (Character.getNumericValue(curr) == Character.getNumericValue(prev) + 1                 || (prev == 'z' && curr == 'a')) {                 maxLen++;             } else {                 maxLen = 1;             }                           count[curr - 'a'] = Math.max(count[curr - 'a'], maxLen);         }                   for (int i = 0; i < count.length; i++) {             ans += count[i];         }                           return ans;     } }