Introduction

In this blog post, we will explore how to solve the LeetCode problem "2678" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given a 0-indexed array of strings details. Each element of details provides information about a given passenger compressed into a string of length 15. The system is such that: The first ten characters consist of the phone number of passengers. The next character denotes the gender of the person. The following two characters are used to indicate the age of the person. The last two characters determine the seat allotted to that person. Return the number of passengers who are strictly more than 60 years old. Example 1: Input: details = ["7868190130M7522","5303914400F9211","9273338290F4010"] Output: 2 Explanation: The passengers at indices 0, 1, and 2 have ages 75, 92, and 40. Thus, there are 2 people who are over 60 years old. Example 2: Input: details = ["1313579440F2036","2921522980M5644"] Output: 0 Explanation: None of the passengers are older than 60. Constraints: 1 <= details.length <= 100 details[i].length == 15 details[i] consists of digits from '0' to '9'. details[i][10] is either 'M' or 'F' or 'O'. The phone numbers and seat numbers of the passengers are distinct.

Explanation

• Direct Age Extraction: Extract the age directly from the string using slicing, convert it to an integer, and compare it with 60.
  • Iterate and Count: Loop through the details array, applying the age extraction and comparison to each element, and increment a counter if the condition is met.
  • Avoid Unnecessary Operations: The algorithm avoids unnecessary string manipulation or data structures, focusing on efficient extraction and comparison.

• Runtime Complexity: O(n), where n is the number of strings in the details array. Storage Complexity: O(1).

Code

    def count_passengers(details):
    """
    Counts the number of passengers who are strictly more than 60 years old.

    Args:
        details: A list of strings, where each string represents a passenger's information.

    Returns:
        The number of passengers who are strictly more than 60 years old.
    """

    count = 0
    for detail in details:
        age = int(detail[11:13])
        if age > 60:
            count += 1
    return count