[LeetCode OJ] 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?

 1 class Solution {

 2 public:

 3     int candy(vector<int> &ratings) {

 4         vector<int> candy_number(ratings.size(), 1);

 5         //不用迭代器，改用下标索引实现，这样代码看起来更加简洁

 6         for(int i=1; i<ratings.size(); ++i)

 7         {

 8            //保障当右边的rating比左边的高时，则右边分得的糖果比左边多

 9             if( ratings[i] > ratings[i-1])      //eg：输入[4 2 3 4 1],最少的分法是[2 1 2 3 1],分发9个糖果

10                 candy_number[i] = (candy_number[i] > candy_number[i-1]+1) ? candy_number[i] : candy_number[i-1]+1;

11         }

12         

13 

14         for(int i=ratings.size()-2; i>=0; --i)   

15         {

16             //保障当左边的rating比右边的高时，则左边分得的糖果比右边多

17             if( ratings[i] > ratings[i+1])

18                 candy_number[i] = (candy_number[i] > candy_number[i+1]+1) ? candy_number[i] : candy_number[i+1]+1;

19         }

20 

21         int total=0;

22         for(int i=0; i!=ratings.size(); ++i)

23             total = total + candy_number[i];

24 

25         return total;

26     }

27 };