LeetCode 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?

 

解法：从左到右比较，第一个发1个，下一个比前一个rating高就+1，否则发1个。

　　　然后从右到左，最后一个发1个，前一个比后一个rating高就+1,否则发1个。

　　取两次得到的值的最大值，然后累加。

 

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