How do you solve Find the Original Typed String I on LeetCode?

Find the Original Typed String I (LeetCode #3330) 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: Identifying groups of consecutive characters is crucial for determining possible original strings.

What is the brute force solution for Find the Original Typed String I?

The brute force approach for Find the Original Typed String I is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute-force approach involves generating all possible original strings by removing one occurrence of any character that appears consecutively. This helps us understand how many variations can be created from the final string. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Find the Original Typed String I?

Find the Original Typed String I uses the following concepts: String. The recommended patterns to study are: Two Pointers, Sliding Window, Hash Map.

What are the interview tips for Find the Original Typed String I?

Always start with a simple approach to understand the problem before optimizing. Clearly explain your thought process and how you are counting variations. Practice identifying patterns in string manipulation problems.

What are common mistakes when solving Find the Original Typed String I?

Failing to account for groups of characters that are not consecutive. Not properly incrementing the counter when encountering groups of more than one character.

#3330

Find the Original Typed String I

Easy

StringTwo PointersSliding WindowHash Map

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	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 count the number of possible original strings. By tracking groups of consecutive characters, we can efficiently determine how many variations can be formed.

⚙️

Algorithm

4 steps

1Step 1: Initialize a counter to 1 for the original string.
2Step 2: Traverse the string while counting consecutive characters.
3Step 3: For each group of consecutive characters, if the count is more than 1, increment the counter.
4Step 4: Return the counter as the total number of possible original strings.

solution.py12 lines

1def count_possible_originals(word):
2    count = 1
3    n = len(word)
4    i = 0
5    while i < n:
6        j = i
7        while j < n and word[j] == word[i]:
8            j += 1
9        if j - i > 1:
10            count += 1
11        i = j
12    return count

ℹ

Complexity note: The complexity is O(n) because we only traverse the string once, counting groups of consecutive characters without any nested iterations.

1Identifying groups of consecutive characters is crucial for determining possible original strings.
2Each group of consecutive characters can contribute to the count of possible original strings.

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