How hard is LeetCode 2262. Total Appeal of A String?

LeetCode 2262. Total Appeal of A String is rated Hard on LeetCode.

What is the time complexity of LeetCode 2262. Total Appeal of A String?

The Python solution on this page runs in O(n).

What is the space complexity of LeetCode 2262. Total Appeal of A String?

The Python solution on this page uses O(|\Sigma|), where n is the length of the string s, and |\Sigma| is the size of the character set auxiliary space.

What topics does LeetCode 2262. Total Appeal of A String cover?

LeetCode 2262. Total Appeal of A String is tagged Hash Table, String and Dynamic Programming on LeetCode.

Total Appeal of A String — LeetCode 2262 Python Solution

HardHash TableStringDynamic Programming

Problem: #2262
Pattern: Dynamic Programming
Reading time: 2 min
Source: leetcode.com

The problem

The appeal of a string is the number of distinct characters found in the string. For example, the appeal of "abbca" is 3 because it has 3 distinct characters: 'a', 'b', and 'c'.

Example

Input: s = "abbca"
Output: 28
Explanation: The following are the substrings of "abbca":

Python solution

Python

class Solution:
    def appealSum(self, s: str) -> int:
        ans = t = 0
        pos = [-1] * 26
        for i, c in enumerate(s):
            c = ord(c) - ord('a')
            t += i - pos[c]
            ans += t
            pos[c] = i
        return ans

Complexity

Measure	Complexity
Time	O(n)
Space	O(\|\Sigma\|), where n is the length of the string s, and \|\Sigma\| is the size of the character set auxiliary

Pattern: Dynamic Programming

Define a state, write the transition, and stop recomputing the same subproblem. LeetCode 2262. Total Appeal of A String is filed here because LeetCode tags it Dynamic Programming, which is the vocabulary this hub collects.

The dynamic programming guide has the Python template for the pattern and the 481 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 2262. Total Appeal of A String?: LeetCode 2262. Total Appeal of A String is rated Hard on LeetCode.
What is the time complexity of LeetCode 2262. Total Appeal of A String?: The Python solution on this page runs in O(n).
What is the space complexity of LeetCode 2262. Total Appeal of A String?: The Python solution on this page uses O(|\Sigma|), where n is the length of the string s, and |\Sigma| is the size of the character set auxiliary space.
What topics does LeetCode 2262. Total Appeal of A String cover?: LeetCode 2262. Total Appeal of A String is tagged Hash Table, String and Dynamic Programming on LeetCode.