Given a string s
, return the number of distinct
substrings of s
.
A substring of a string is obtained by deleting any number of characters (possibly zero) from the front of the string and any number (possibly zero) from the back of the string.
Example 1:
Input: s = "aabbaba" Output: 21 Explanation: The set of distinct strings is ["a","b","aa","bb","ab","ba","aab","abb","bba","aba","aabb","abba","bbab","baba","aabba","abbab","bbaba","aabbab","abbaba","aabbaba"]
Example 2:
Input: s = "abcdefg" Output: 28
Constraints:
1 <= s.length <= 500
s
consists of lowercase English letters.Follow up: Can you solve this problem in
O(n)
time
complexity?
Hints:
Hint 1
Calculate the prefix hashing array for s.
Hint 2
Use the prefix hashing array to calculate the hashing value of each substring.
Hint 3
Compare the hashing values to determine the unique substrings.
Hint 4
There could be collisions if you use hashing, what about double hashing.