135. Candy

There are N children standing in a line. Each child is assigned a rating value.

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.

What is the minimum candies you must give?

 

public class Solution {
    public int candy(int[] ratings) {
        if(ratings.length == 0){
            return 0;
        }
        if(ratings.length == 1){
            return 1;
        }
        int sum = 0;
        int candy[] = new int[ratings.length];
        Arrays.fill(candy, 1);
        for(int i = 1; i < ratings.length; i++){
            if(ratings[i] > ratings[i - 1])
                candy[i] = candy[i-1]+1;
        }
        for(int i = ratings.length - 1; i > 0; i--){
            if(ratings[i-1] > ratings[i])
                candy[i-1] = Math.max(candy[i] + 1,candy[i-1]);
        }
        for(int i = 0; i < candy.length ; i ++){
            sum += candy[i];
        }
        return sum;
    }
}