How do you solve Percentage of Letter in String on LeetCode?

Percentage of Letter in String (LeetCode #2278) 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: Counting occurrences is crucial for percentage calculations.

What is the brute force solution for Percentage of Letter in String?

The brute force approach for Percentage of Letter in String is Brute Force, with O(n) time complexity and O(1) space complexity. The brute force approach involves counting the occurrences of the specified letter in the string and then calculating the percentage based on the total length of the string. This is straightforward but can be inefficient for larger strings. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Percentage of Letter in String?

Percentage of Letter in String uses the following concepts: String. The recommended patterns to study are: Counting occurrences, String manipulation.

What are the interview tips for Percentage of Letter in String?

Always clarify the problem statement and constraints. Discuss your thought process and approach before coding. Test your solution with different inputs to ensure correctness.

What are common mistakes when solving Percentage of Letter in String?

Forgetting to round down the percentage. Not handling edge cases like empty strings.

#2278

Percentage of Letter in String

Easy

StringCounting occurrencesString manipulation

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 is similar to the brute force approach but focuses on a single pass through the string to count occurrences. This ensures efficiency while maintaining clarity.

⚙️

Algorithm

4 steps

1Step 1: Initialize a counter to zero.
2Step 2: Loop through each character in the string and increment the counter if it matches the specified letter.
3Step 3: Calculate the percentage using integer division to avoid floating-point operations.
4Step 4: Return the percentage.

solution.py3 lines

1def percentage_of_letter(s, letter):
2    count = s.count(letter)
3    return (count * 100) // len(s)

ℹ

Complexity note: The time complexity is O(n) because we still need to traverse the string once. The space complexity is O(1) since we are using a fixed amount of space for the counter.

1Counting occurrences is crucial for percentage calculations.
2Using built-in functions can simplify code and improve readability.

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