[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;
}
}
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