How do you solve Reverse Degree of a String on LeetCode?

Reverse Degree of a String (LeetCode #3498) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Understanding character encoding is crucial for calculating positions.

What is the time complexity of Reverse Degree of a String?

The optimal solution for Reverse Degree of a String runs in O(n) time and uses O(1) space. The complexity is O(n) due to a single traversal of the string, with constant time calculations.

What is the brute force solution for Reverse Degree of a String?

The brute force approach for Reverse Degree of a String is Brute Force, with O(n) time complexity and O(1) space complexity. Calculate the reverse degree by iterating through each character, determining its position in the reversed alphabet, and multiplying it by its index in the string. This approach is straightforward but inefficient for larger strings. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Reverse Degree of a String?

Reverse Degree of a String uses the following concepts: String, Simulation. The recommended patterns to study are: Hash Map, Array.

What are the interview tips for Reverse Degree of a String?

Clarify the problem statement and constraints. Think through edge cases, like single-character strings. Explain your thought process clearly as you code.

What are common mistakes when solving Reverse Degree of a String?

Forgetting to adjust for 1-indexing. Incorrectly calculating the reverse position of characters.

#3498

Reverse Degree of a String

Easy

StringSimulationHash MapArray

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

The optimal solution leverages a single pass through the string to compute the reverse degree efficiently. Each character's reverse position is calculated directly, ensuring a linear time complexity.

⚙️

Algorithm

3 steps

1Step 1: Initialize a total variable to 0.
2Step 2: Iterate through the string, calculating the reverse position for each character.
3Step 3: Multiply the reverse position by the 1-indexed position and add to total.

solution.py5 lines

1def reverse_degree(s):
2    total = 0
3    for i, char in enumerate(s):
4        total += (26 - (ord(char) - ord('a'))) * (i + 1)
5    return total

ℹ

Complexity note: The complexity is O(n) due to a single traversal of the string, with constant time calculations.

1Understanding character encoding is crucial for calculating positions.
21-indexing is important for accurate position calculations.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.