Introduction

In this blog post, we will explore how to solve the LeetCode problem "881" 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 an array people where people[i] is the weight of the ith person, and an infinite number of boats where each boat can carry a maximum weight of limit. Each boat carries at most two people at the same time, provided the sum of the weight of those people is at most limit. Return the minimum number of boats to carry every given person. Example 1: Input: people = [1,2], limit = 3 Output: 1 Explanation: 1 boat (1, 2) Example 2: Input: people = [3,2,2,1], limit = 3 Output: 3 Explanation: 3 boats (1, 2), (2) and (3) Example 3: Input: people = [3,5,3,4], limit = 5 Output: 4 Explanation: 4 boats (3), (3), (4), (5) Constraints: 1 <= people.length <= 5 104 1 <= people[i] <= limit <= 3 104

Explanation

Here's the breakdown of the solution:

• Sort the array: Sorting allows us to efficiently pair the lightest person with the heaviest possible person.
• Two-pointer approach: Use two pointers, one at the beginning (lightest) and one at the end (heaviest) of the sorted array.

• Greedy Pairing: If the lightest and heaviest person can fit in one boat, pair them and move both pointers. Otherwise, the heaviest person takes a boat alone, and we move the right pointer.

• Runtime Complexity: O(n log n) due to sorting. Storage Complexity: O(1) (in-place sorting if possible, otherwise O(n) depending on the sorting algorithm).

Code

    def numRescueBoats(people, limit):
    people.sort()
    left, right = 0, len(people) - 1
    boats = 0
    while left <= right:
        if people[left] + people[right] <= limit:
            left += 1
            right -= 1
        else:
            right -= 1
        boats += 1
    return boats