Candy

Problem Description

There are n children standing in a line. Each child is assigned a rating value given in the integer array ratings.

You are giving candies to these children subjected to the following requirements:

1. Each child must have at least one candy.
2. Children with a higher rating get more candies than their neighbors.

Return the minimum number of candies you need to have to distribute the candies to the children.

Examples

Example 1:

Input: ratings = [1,0,2]
Output: 5
Explanation: You can allocate to the first, second and third child with 2, 1, 2 candies respectively.

Example 2:

Input: ratings = [1,2,2]
Output: 4
Explanation: You can allocate to the first, second and third child with 1, 2, 1 candies respectively.
The third child gets 1 candy because it satisfies the above two conditions.

Constraints

• n == ratings.length
• 1 <= n <= 2 * 10^4
• 0 <= ratings[i] <= 2 * 10^4

Code Template

class Solution:
    def candy(self, ratings: List[int]) -> int:
        # Write your code here
        pass

Solutions

• Solution 1: This approach uses two passes to ensure both neighbor conditions are satisfied.
• Solution 2: This approach uses slope counting to efficiently calculate the required candies in a single pass.

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