[leetcode 135] Candy

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本文探讨了如何根据儿童评分公平分配最少数量的糖果。确保每个孩子至少获得一颗糖果，并且评分较高的孩子比邻居获得更多糖果。通过双向遍历算法实现，首先从前向后确保递增序列，再从后向前检查下降序列。

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?

class Solution {
public:
    int candy(vector<int> &ratings) {
        const int n = ratings.size();
        vector<int> candy(n,0);
        for (int i = 1, inc = 1; i < n; i++) {
            if (ratings[i] > ratings[i-1]) {
                candy[i] = max(inc++, candy[i]);
            } else {
                inc = 1;
            }
        }
        for (int j = n - 2, inc = 1; j >= 0; j--) {
            if (ratings[j] > ratings[j+1]) {
                candy[j] = max(inc++, candy[j]);
            } else {
                inc = 1;
            }
        }
        return accumulate(&candy[0], &candy[0]+n, n);
    }
};