#3 LeetCode ( Q:(135) Candy )

LeetCode Candy Question
Level : Hard
Challenge : 3

Question URL :
https://leetcode.com/problems/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?

Example 1:

Input: [1,0,2]
Output: 5
Explanation: You can allocate to the first, second and third child with 2, 1, 2 candies respectively.

Example 2:

Input: [1,2,2]
Output: 4
Explanation: You can allocate to the first, second and third child with 1, 2, 1 candies respectively.
             The third child gets 1 candy because it satisfies the above two conditions.

Solution — Java

class Solution {
public int candy(int[] ratings) {
if(ratings==null || ratings.length==0) return 0;
int[] candies= new int[ratings.length];
candies[0]=1;
for(int i=1;i<ratings.length;i++){
if(ratings[i]>ratings[i-1]) candies[i]=candies[i-1]+1;
else candies[i]=1;
}
int sum=candies[ratings.length-1];
for(int i=ratings.length-2;i>=0;i — ){
if(ratings[i]>ratings[i+1]){
candies[i]=Math.max(candies[i+1]+1,candies[i]);
}
sum+=candies[i];
}
return sum;
}
}

Goal : 3 / 1000 (Question)