[LeetCode] 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?

例子：

input ： 　　　  1 1 7 6 5 9 7

第一次扫描：　　1 1 2 1 1 2 1

第二次扫描：　　1 1  3  2  1 2 1

class Solution {
public:
    int candy(vector<int> &ratings) {
        int res = 0;
        int n = ratings.size();
        if (n == 0) {
            return res;
        }
        int *t = new int[n];
        for (int i = 0; i < n; ++i) {
            t[i] = 1;
        }
        //从左向右扫描  ，保证当前比前一个多
        for (int i = 1; i < n; ++i) {
            if (ratings[i] > ratings[i-1]) {
                t[i] = t[i-1] + 1;
            }
        }
        //从右向左扫描， 保证当前比后一个多     
        for(int i = n-2;i >= 0;i--)
        {             
            //如果第i个的小孩的权值比i+1个小孩高,但是糖的数目却小或者相等，那么i的糖数目等于i+1的糖数目+1。             
            if(ratings[i] > ratings[i+1] && t[i] <= t[i+1])
            {                 
                t[i] = t[i+1] + 1;            
            }      
        }
        for (int i = 0; i < n; ++i) {
            res += t[i];
        }
        return res;
    }
};