Leetcode #781 - Rabbits in Forest

21 Apr, 2025

There is a forest with an unknown number of rabbits. We asked n rabbits:

“How many rabbits have the same color as you?”

Each rabbit replied with a number, and we collected these answers in an integer array answers, where answers[i] is the response of the i-th rabbit.

Your task is to determine the minimum number of rabbits that could be in the forest based on these replies.

🔍 Example 1

Input:
answers = [1, 1, 2]

Output:
5

Explanation:

• The two rabbits that answered 1 could be the same color (e.g., red).
• The rabbit that answered 2 cannot be red; otherwise, it would contradict the others.
• Assume the rabbit that answered 2 is blue. Then there must be 2 more blue rabbits that didn't answer (since it said “2 others like me”).

So the minimum number of rabbits is:

• 3 (those who answered) + 2 (additional blue rabbits) = 5

🔍 Example 2

Input:
answers = [10, 10, 10]

Output:
11

Explanation:

• Each rabbit says there are 10 others like them → group size = 11.
• But with 3 rabbits giving the same answer, we can fit them into one group of 11 (with 8 unaccounted-for rabbits that didn't answer).
• So we assume one full group → 11 rabbits

✅ Constraints

• 1 <= answers.length <= 1000
• 0 <= answers[i] < 1000

🎯 Would you like to try it yourself? Click here to solve it on Leetcode!

🤔 Curious how I did? [Check out my solution!] (https://leetcode.com/problems/rabbits-in-forest/solutions/6674788/leetcode-781-rabbits-in-forest-by-cpn3kq-qri3/)

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