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?
解题思路：
双向爬坡问题，从前往后、从后往前各扫一遍，JAVA实现如下：
public int candy(int[] ratings) {
int sum = 0;
int[] candies = new int[ratings.length];
for (int i = 0; i < ratings.length - 1; i++)
if (ratings[i] < ratings[i + 1])
candies[i + 1] = candies[i] + 1;
for (int i = ratings.length - 2; i >= 0; i--)
if (ratings[i + 1] < ratings[i])
candies[i] = Math.max(candies[i], candies[i + 1] + 1);
for (int i = 0; i < candies.length; i++)
sum += 1 + candies[i];
return sum;
}