Number of Segments in a String

This problem is about counting the number of segments in a given string where a segment is defined as a continuous sequence of non-space characters.

Here’s the solution:

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class Solution:
    def countSegments(self, s: str) -> int:
        # Split the string by spaces to get the segments
        segments = s.split()
        # Return the number of segments
        return len(segments)

The function first splits the string by spaces, which divides it into segments of non-space characters. It then returns the number of segments, which is the length of the resulting list from the split operation.

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class Solution:
    def countSegments(self, s: str) -> int:
        count = 0

        for i in range(len(s)):
            if s[i] != ' ' and (i == 0 or s[i-1] == ' '):
                count += 1

        return count

Problem Classification

This problem can be classified into the following categories:

  1. String Processing: The problem involves dealing with strings and requires operations to be performed on the strings.

  2. Counting Problem: This problem requires counting the number of certain elements, specifically segments of non-space characters, in a string.

  3. Segmentation or Partitioning: The problem involves breaking down the string into smaller segments based on a certain condition or delimiter.

  4. Language Processing: We are essentially trying to count the number of words in a string, which can be seen as a very basic form of language processing or tokenization.

Language Agnostic Coding Drills

The problem involves processing a string to count the number of non-space character segments, or in other words, words. Here are the various concepts and steps to approach this problem:

  1. Understanding Strings: Understand what strings are, how to access individual characters, and how to traverse a string using indexing.

  2. String Manipulation: Learn how to perform basic operations on strings such as comparing characters.

  3. Counting: Understand how to use a counter variable to keep track of certain conditions while processing data.

  4. Condition Checking: Learn how to use conditions to check for specific requirements. In this problem, we need to identify when a non-space character segment (word) starts.

The step-by-step approach for the problem would look like this:

  1. Start with initializing a counter variable to 0. This will keep track of the number of segments we encounter.

  2. Loop through the string, checking each character one by one.

  3. Inside the loop, check if the current character is a non-space character and if it is the start of a new segment. A new segment starts when the current character is a non-space character and either it’s the first character in the string or the previous character was a space.

  4. If the current character satisfies the conditions in step 3, increment the counter by 1.

  5. Continue this until all characters in the string have been checked.

  6. Return the counter, which will have the total number of segments in the string.

By understanding and implementing these individual concepts, we can then combine them to solve the problem. Each concept can be practised individually, then slowly combined to build up to the final solution. This helps in reinforcing learning and understanding the process of problem solving.

Targeted Drills in Python

  1. Understanding Strings:

    Learn how to define a string, access individual characters, and traverse it using indexing.

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    s = "hello"
print(s[0])  # print the first character of the string
for character in s:  # print each character of the string one by one
    print(character)

  2. String Manipulation:

    Understand how to compare characters in Python.

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    a = 'a'
b = 'b'
print(a == b)  # will return False
space = ' '
print(a == space)  # will return False
print(space == space)  # will return True

  3. Counting:

    Understand how to use a counter to keep track of certain conditions.

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    counter = 0
for i in range(10):  # count the number of even numbers from 0 to 9
    if i % 2 == 0:
        counter += 1
print(counter)  # will print 5

  4. Condition Checking:

    Practice checking for specific requirements.

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    s = "hello"
if s[0] == 'h':  # check if the first character is 'h'
    print("First character is h")

Finally, let’s put all these concepts together to solve the problem:

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s = "Hello, my name is Inigo Montoya"
count = 0
for i in range(len(s)):
    if s[i] != ' ' and (i == 0 or s[i-1] == ' '):
        count += 1
print(count)  # will print 6