[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.

AC代码：

public class Solution {
    public int findSubstringInWraproundString(String p) {
         int len = p.length();
        if(len == 0 || len ==1 ){
            return len;
        }

        int[] cnt = new int[26];
        int tmp = 1;
        int res = 0;
        for(int i =0 ; i  < len ; ++i){
            if(i > 0 && (p.charAt(i) - p.charAt(i-1) == 1 || (p.charAt(i)== 'a' && p.charAt(i-1) == 'z'))){
                ++tmp;
            }else{
                tmp = 1;
            }
            if(tmp > cnt[p.charAt(i) - 'a']){
                res +=(tmp - cnt[p.charAt(i) - 'a']);
                cnt[p.charAt(i) - 'a'] = tmp;
            }
        }
        return res;
    }
}