Candy

两个数组，从两边扫描。

题目中，如果rating相等的时候，不要求得到的糖一样，不是很科学。真正面试时要问清楚requirement。

public class Solution {
    public int candy(int[] ratings) {
        if(ratings == null || ratings.length == 0) return 0; 
        int len = ratings.length;
        int[] left = new int[len];
        int[] right = new int[len];
        left[0] = 1;
        right[len - 1] = 1;
        int result = 0;
        for(int i = 1; i < len; i++) {
            if(ratings[i] > ratings[i - 1]) {
                left[i] = left[i - 1] + 1;
            //} else if(ratings[i] == ratings[i - 1]) {
            //    left[i] = left[i - 1];
            } else {
                left[i] = 1;
            }
        }
        for(int i = len - 2; i >= 0; i--) {
            if(ratings[i] > ratings[i + 1]) {
                right[i] = right[i + 1] + 1;
            //} else if(ratings[i] == ratings[i + 1]) {
            //    right[i] = right[i + 1];
            } else {
                right[i] = 1;
            }
        }
        for(int i = 0; i < len; i++) {
            result += Math.max(left[i], right[i]);
        }
        return result;
    }
}