Candy

题目描述：
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?

分析：这是一道非常经典的算法题，对每一个人而言，至少有一颗糖，所以数组初始化为一，然后进行由前到后，由后到前两次遍历，来维护最小数需要的合法糖果数即可。

代码如下：

    int candy(vector<int>& ratings) { 
     vector<int> ans(ratings.size(),1);
     for (int i = 1; i < ratings.size(); i++)
     {
         if(ratings[i]>ratings[i-1])
             ans[i]=ans[i-1]+1;
     }
     for (int i= ratings.size()-1; i>0 ; i--)
     {
         if(ratings[i-1]>ratings[i])
             ans[i-1]=max(ans[i]+1,ans[i-1]);
     }
     int result=0;
     for (int i = 0; i < ratings.size(); i++)
     {
         result+=ans[i];
     }
     return result;
    }