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?

分别从左右两边找出所有递增序列并记录需要填充的值（k), 最后遍历一次取每个位置最大的需要取值（还要加上cnt--每人至少一块）。
按照题目的答案要求，似乎对于同等身高的人没有额外要求--也就是说尽可能少给（比如身高序列 1，2，2 ； 那给糖果就是1，2，1就行了，尽管后两人身高一样）

如果要求挨着的身高相同的人一样多，那把下边程序里边给k赋值0的条件中的等于去掉就行了。

class Solution {
public:
    int candy(vector<int> &ratings) {
        int cnt = ratings.size();
        vector<int> fromleft(cnt, 0);
        int k = 0;
        for (int i = 1; i < cnt; i++) {
            if (ratings[i] > ratings[i - 1]) {
                k++;
            } else if (ratings[i] <= ratings[i - 1]) {
                k = 0;
            }
            fromleft[i] = k;
        }
        
        vector<int> fromright(cnt, 0);
        k = 0;
        for (int i = cnt - 2; i >= 0; i--) {
            if (ratings[i] > ratings[i + 1]) {
                k++;
            } else if (ratings[i] <= ratings[i + 1]) {
                k = 0;
            }
            fromright[i] = k;
        }
        
        int ret = cnt + max(fromleft[0], fromright[0]);
        for (int i = 1; i < cnt; i++) {
            ret +=  max(fromleft[i], fromright[i]);
        }
        
        return ret;
    }
};