Understand what the interviewer is asking for by using test cases and questions about the problem.
- Established a set (2-3) of test cases to verify their own solution later.
- Established a set (1-2) of edge cases to verify their solution handles complexities.
- Have fully understood the problem and have no clarifying questions.
- Have you verified any Time/Space Constraints for this problem?
HAPPY CASE
Input: answers = [1,1,2]
Output: 5
EDGE CASE
Input: answers = [10,10,10]
Output: 11
Match what this problem looks like to known categories of problems, e.g. Linked List or Dynamic Programming, and strategies or patterns in those categories.
Plan the solution with appropriate visualizations and pseudocode.
General Idea:
1. Create a hashtable counts
2. Set sum = 0
3. For each answer in answers
If answer == 0, sum += 1
If answer not in counts:
counts[answer] = 1
sum += answer + 1
If counts[answer] < answer + 1
counts[answer] ++
else
counts[answer] += 1
sum += answer + 1
4. Return sum
⚠️ Common Mistakes
To minimize the total number of rabbits, we can divide these y rabbits into groups, each group having a size of (x+1) and the rabbits within the same group having the same color. If y%(x+1)>0, then the last y%(x+1) rabbits have the same color as some other rabbits that don't share their information in this poll. These last y%(x+1) and those rabbits that don't participate should add up to (x+1) (Otherwise, the claim that x other rabbits have the same color is a false claim).
Implement the code to solve the algorithm.
class Solution(object):
def numRabbits(self, answers):
count = collections.Counter(answers)
return sum(-v % (k+1) + v for k, v in count.iteritems())
class Solution {
public int numRabbits(int[] answers) {
int[] count = new int[1000];
for (int x: answers) count[x]++;
int ans = 0;
for (int k = 0; k < 1000; ++k)
ans += Math.floorMod(-count[k], k+1) + count[k];
return ans;
}
}
Review the code by running specific example(s) and recording values (watchlist) of your code's variables along the way.
Evaluate the performance of your algorithm and state any strong/weak or future potential work.