828. Count Unique Characters of All Substrings of a Given String
Hard
50 Points
Hash Table
String
Dynamic Programming
Let's define a function countUniqueChars(s) that returns the number of unique characters in s.
Given a string s, return the sum of countUniqueChars(t) where t is a substring of s. The test cases are generated such that the answer fits in a 32-bit integer.
Notice that some substrings can be repeated so in this case you have to count the repeated ones too.
Examples
Example 1
Input: s = "ABC"
Output: 10
Explanation: All possible substrings are: "A","B","C","AB","BC" and "ABC".
Every 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.
828. Count Unique Characters of All Substrings of a Given String
Hard
50 Points
Hash Table
String
Dynamic Programming
Let's define a function countUniqueChars(s) that returns the number of unique characters in s.
Given a string s, return the sum of countUniqueChars(t) where t is a substring of s. The test cases are generated such that the answer fits in a 32-bit integer.
Notice that some substrings can be repeated so in this case you have to count the repeated ones too.
Examples
Example 1
Input: s = "ABC"
Output: 10
Explanation: All possible substrings are: "A","B","C","AB","BC" and "ABC".
Every 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.
Count Unique Characters of All Substrings of a Given String - Practice Coding | SlaveCode