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You are given a string s, and you need to count the number of segments in the string. A segment is defined to be a contiguous sequence of non-space characters.

Write a function countSegments that returns the number of segments in the string s.

Example:

Input: s = "Hello, my name is John"
Output: 5

Clarifying Questions:

  1. Does the input string contain only ASCII characters?
    • Yes, you can assume the input contains only ASCII characters.
  2. Can the input string be empty?
    • Yes, the input string can be empty. If the string is empty, the expected output should be 0.
  3. Should I handle leading, trailing, or multiple spaces?
    • Yes, your solution should handle leading, trailing, and multiple consecutive spaces between words correctly.

Strategy:

The approach to solve this problem involves the following steps:

  1. Strip leading and trailing spaces: This will help in simplifying our count. Even though this step is not necessary for counting, it might make the process more intuitive.
  2. Split the string by spaces: Using str.split() will split the string into a list of words, automatically ignoring any number of spaces between words.
  3. Count the resulting list: The final list’s length will give us the number of segments.

Using Python’s str.split() method is efficient because it handles multiple spaces and returns a list of substrings split by the whitespace.

Code:

def countSegments(s: str) -> int:
    # Split the string by spaces and count the segments
    return len(s.split())

# Example usage
s = "Hello, my name is John"
print(countSegments(s))  # Output: 5

Time Complexity:

The time complexity of the solution is O(n), where n is the length of the string s. This is because the split() method iterates through the entire string once to split the words.

Explanation:

  1. s.split(): The split() method splits the string at each sequence of spaces, effectively handling multiple spaces as well as leading and trailing spaces. It returns a list of words.
  2. len(): The len() function calculates the number of elements in the list returned by split(), which are the segments of the string.

In this way, the function countSegments counts the number of segments (words) in the given string efficiently.

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