LeetCode:Candy

Posted 2020-07-13 walker lee

Candy

Total Accepted: 52308 Total Submissions: 231427 Difficulty: Hard

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?

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 Greedy

思路：

1.先给每个小孩分1 个candy；

2.从左往右：如果，左<右，则右边小孩加1颗candy；

2.从右往左：如果，左>右，则左边小孩要比右边的candy多。

java code:

public class Solution {
    public int candy(int[] ratings) {
        
        int len = ratings.length;
        int[] candies = new int[len];
        for(int i=0;i<len;i++) candies[i] = 1;
        
        for(int i=1;i<len;i++) {
            if(ratings[i-1] < ratings[i])
                candies[i] = candies[i-1] + 1;
        }
        
        for(int i=len-1;i>0;i--) {
            if(ratings[i-1] > ratings[i])
                candies[i-1] = Math.max(candies[i-1], candies[i]+1);
        }
        
        int ans = 0;
        for(int candy : candies) {
            ans += candy;
        }
        
        return ans;
    }
}