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:
Each child must have at least one candy. 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.
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 * 104
- 0 <= ratings[i] <= 2 * 104
public int candy(int[] ratings) {
int candies[] = new int[ratings.length];
Arrays.fill(candies, 1);// Give each child 1 candy
for (int i = 1; i < candies.length; i++){// Scan from left to right, to make sure right higher rated child gets 1 more candy than left lower rated child
if (ratings[i] > ratings[i - 1]) candies[i] = (candies[i - 1] + 1);
}
for (int i = candies.length - 2; i >= 0; i--) {// Scan from right to left, to make sure left higher rated child gets 1 more candy than right lower rated child
if (ratings[i] > ratings[i + 1]) candies[i] = Math.max(candies[i], (candies[i + 1] + 1));
}
int sum = 0;
for (int candy : candies)
sum += candy;
return sum;
}