LeetCode OJ：Candy（糖果问题）

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?

一个抠门的人要给一群孩子发糖果，在保证在相邻的孩子之间的rating较高者应该比rating低的获得更多的糖果的情况下，怎样发最少的糖果。

左右各遍历一次即可，代码如下所示：

class Solution {
public:
    int candy(vector<int>& ratings) {
        int sz = ratings.size();
        vector<int>candy(sz, 0);
        if(sz == 0) return 0;
        if(sz == 1) return 1;
        candy[0] = 1;
        for(int i = 1; i < sz; ++i){
            if(ratings[i] > ratings[i-1])
                candy[i] = candy[i-1] + 1;
            else
                candy[i] = 1;
        }
        for(int i = sz-2; i >= 0; i--){
            if(ratings[i] > ratings[i+1])
                if(candy[i] <= candy[i+1])
                    candy[i] = candy[i+1] + 1;
        }
        int sum = accumulate(candy.begin(), candy.end(), 0);
        return sum;
    }
};