[leetcode]467. Unique Substrings in Wraparound String

题目链接：https://leetcode.com/problems/unique-substrings-in-wraparound-string/#/description

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: 1Explanation: Only the substring "a" of string "a" is in the string s.

Example 2:

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

Example 3:

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

class Solution {public:    int findSubstringInWraproundString(string p) {        vector<int> letters(26,0);        int len=0;        for(int i=0;i<p.size();i++)        {            int cur=p[i]-'a';            if(i>0 && p[i-1]!=(cur+26-1)%26+'a') len=0;            letters[cur]=max(letters[cur],++len);        }        return accumulate(letters.begin(),letters.end(),0);    }};