Package g0801_0900.s0828_count_unique_characters_of_all_substrings_of_a_given_string

Class Solution

java.lang.Object
g0801_0900.s0828_count_unique_characters_of_all_substrings_of_a_given_string.Solution
public class Solution extends java.lang.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 <= 105
  • s consists of uppercase English letters only.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    uniqueLetterString(java.lang.String s)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • uniqueLetterString

      public int uniqueLetterString(java.lang.String s)