leetCode---Candy

一. 题目：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?

二. 思路分析


  题目大意：有N个孩子站在一条线上。每个孩子被分配一个评分值。你给这些孩子的糖果受到以下要求：每个孩子必须至少有一个糖果。具有较高评级的儿童比邻居获得更多的糖果。你必须给予的最少糖果是什么？ 思路分析：这是一个贪心算法的应用，先从左到右扫描一遍，使得右边比左边得分高的小朋友糖果数比左边多。再从右到左扫描一遍，使得左边比右边得分高的小朋友糖果数比右边多。代码如下：

class Solution { public:         int candy(vector<int>& ratings) {                 int len = ratings.size(), res = 0, i;                 if(len>0){                         vector<int> number(len,0);            number[0] = 1;                          for(i=1; i<len;++i)                 number[i] = ratings[i]>ratings[i-1]?number[i-1]+1:1;                         for(i=len-2, res = number[len-1]; i>=0;--i){                                 if( (ratings[i]>ratings[i+1]) && number[i]<(number[i+1]+1) )                     number[i] = number[i+1]+1;                                 res += number[i];                         }                 }                 return res;         } };