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) {        std::vector<int> num(ratings.size(), 1);                int inc = 2;        for (int i = 1; i < ratings.size(); ++i) {            if (ratings.at(i) > ratings.at(i - 1)) {                num.at(i) = std::max(inc++, num.at(i));            } else {                inc = 2;            }        }        inc = 2;        for (int i = ratings.size() - 2; i >= 0; --i) {            if (ratings.at(i) > ratings.at(i + 1)) {                num.at(i) = std::max(inc++, num.at(i));            } else {                inc = 2;            }        }        int res = std::accumulate(num.begin(), num.end(), 0);        return res;    }};

原数组为：1 --> 2 --> 5 --> 4 --> 3 --> 2 --> 1step2之后 num数组为：1 --> 2 --> 3 --> 1 --> 1 --> 1 --> 1step3从右向左遍历到idx=2时 : 1 --> 2 --> （3 or 5）--> 4 --> 3 --> 2 --> 1