Watch 10 video solutions for Sum of Scores of Built Strings, a hard level problem involving String, Binary Search, Rolling Hash. This walkthrough by Greg Hogg has 235,694 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
You are building a string s of length n one character at a time, prepending each new character to the front of the string. The strings are labeled from 1 to n, where the string with length i is labeled si.
s = "abaca", s1 == "a", s2 == "ca", s3 == "aca", etc.The score of si is the length of the longest common prefix between si and sn (Note that s == sn).
Given the final string s, return the sum of the score of every si.
Example 1:
Input: s = "babab" Output: 9 Explanation: For s1 == "b", the longest common prefix is "b" which has a score of 1. For s2 == "ab", there is no common prefix so the score is 0. For s3 == "bab", the longest common prefix is "bab" which has a score of 3. For s4 == "abab", there is no common prefix so the score is 0. For s5 == "babab", the longest common prefix is "babab" which has a score of 5. The sum of the scores is 1 + 0 + 3 + 0 + 5 = 9, so we return 9.
Example 2:
Input: s = "azbazbzaz" Output: 14 Explanation: For s2 == "az", the longest common prefix is "az" which has a score of 2. For s6 == "azbzaz", the longest common prefix is "azb" which has a score of 3. For s9 == "azbazbzaz", the longest common prefix is "azbazbzaz" which has a score of 9. For all other si, the score is 0. The sum of the scores is 2 + 3 + 9 = 14, so we return 14.
Constraints:
1 <= s.length <= 105s consists of lowercase English letters.