java.lang.Object
g0801_0900.s0828_count_unique_characters_of_all_substrings_of_a_given_string.Solution

public class Solution extends Object
828 - Count Unique Characters of All Substrings of a Given String\. Hard Let's define a function `countUniqueChars(s)` that returns the number of unique characters on `s`. * For example if `s = "LEETCODE"` then `"L"`, `"T"`, `"C"`, `"O"`, `"D"` are the unique characters since they appear only once in `s`, therefore `countUniqueChars(s) = 5`. Given a string `s`, return the sum of `countUniqueChars(t)` where `t` is a substring of s. Notice that some substrings can be repeated so in this case you have to count the repeated ones too. **Example 1:** **Input:** s = "ABC" **Output:** 10 **Explanation:** All possible substrings are: "A","B","C","AB","BC" and "ABC". Evey substring is composed with only unique letters. Sum of lengths of all substring is 1 + 1 + 1 + 2 + 2 + 3 = 10 **Example 2:** **Input:** s = "ABA" **Output:** 8 **Explanation:** The same as example 1, except `countUniqueChars`("ABA") = 1. **Example 3:** **Input:** s = "LEETCODE" **Output:** 92 **Constraints:** * `1 <= s.length <= 10`5 * `s` consists of uppercase English letters only.
  • Constructor Details

    • Solution

      public Solution()
  • Method Details

    • uniqueLetterString

      public int uniqueLetterString(String s)