Algorithm

Problem Name: 781. Rabbits in Forest

Problem Link: https://leetcode.com/problems/rabbits-in-forest/
 

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

Code Examples

#1 Code Example with Java Programming

Code - Java Programming


class Solution {
    public int numRabbits(int[] answers) {
        Map map = new HashMap<>();
        
        for (int ans : answers) {
            map.put(ans, map.getOrDefault(ans, 0) + 1);
        }
        
        int count = 0;
        
        for (Map.Entry < Integer, Integer> entry : map.entrySet()) {
            
            int valid = entry.getKey() + 1;
            
            if (entry.getValue() <= valid) {
                count += valid;
                map.put(entry.getKey(), 0);
            }
            else {
                int changed = entry.getValue()%valid;
                count += (entry.getValue()/valid)*valid;

                map.put(entry.getKey(), changed);
            }
            
        }
        
        for (Map.Entry < Integer, Integer> entry : map.entrySet()) {
            if (entry.getValue() > 0) {
                count += entry.getKey() + 1;
            }
        }
        
        return count;
    }
}
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Input

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answers = [1,1,2]

Output

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5

#2 Code Example with Python Programming

Code - Python Programming


class Solution:
    def numRabbits(self, answers):
        dic, res = {}, 0
        for ans in answers:
            (dic[ans], res) = (1, res + ans + 1) if ans not in dic or dic[ans] > ans else (dic[ans] + 1, res)
        return res
Copy The Code & Try With Live Editor

Input

x
–
+
cmd
answers = [1,1,2]

Output

x
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cmd
5
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