Introduction

In this blog post, we will explore how to solve the LeetCode problem "781" 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

There is a forest with an unknown number of rabbits. We asked n rabbits "How many rabbits have the same color as you?" and collected the answers in an integer array answers where answers[i] is the answer of the ith rabbit. Given the array answers, return the minimum number of rabbits that could be in the forest. Example 1: Input: answers = [1,1,2] Output: 5 Explanation: The two rabbits that answered "1" could both be the same color, say red. The rabbit that answered "2" can't be red or the answers would be inconsistent. Say the rabbit that answered "2" was blue. Then there should be 2 other blue rabbits in the forest that didn't answer into the array. The smallest possible number of rabbits in the forest is therefore 5: 3 that answered plus 2 that didn't. Example 2: Input: answers = [10,10,10] Output: 11 Constraints: 1 <= answers.length <= 1000 0 <= answers[i] < 1000

Explanation

Here's a breakdown of the solution:

• Group by Answer: The core idea is to group rabbits by their answers. Rabbits giving the same answer could be of the same color.

• Calculate Minimum Rabbits per Group: For each answer x, if we have k rabbits giving that answer, we need to determine the minimum number of rabbits required to satisfy the condition that there are x+1 rabbits of that color.

• Sum the Minimums: Sum the minimum number of rabbits for each answer group to get the overall minimum number of rabbits in the forest.

• Runtime & Storage Complexity: O(n) runtime, O(n) storage.

Code

    def numRabbits(answers):
    """
    Calculates the minimum number of rabbits in the forest.

    Args:
        answers: A list of integers representing the answers of the rabbits.

    Returns:
        The minimum number of rabbits in the forest.
    """

    counts = {}
    for answer in answers:
        counts[answer] = counts.get(answer, 0) + 1

    total_rabbits = 0
    for answer, count in counts.items():
        group_size = answer + 1
        num_groups = (count + group_size - 1) // group_size
        total_rabbits += num_groups * group_size

    return total_rabbits