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?
Runtime: 392 ms
这道题跟Leetcode 一道contain
water的题很像，思想很简单，可以把每个小朋友单独考虑，看下每个小朋友左边有紧邻的小朋友rate降序的个数，再看下该小朋友右边紧邻的小朋友降序的个数，然后就能确定本小朋友的最小“高度”（两降序个数中较大值），即为小朋友应得的糖果。
方法：从前往后，从后往前扫描两遍，并用lowleft[],lowright[]分别记录每个小朋友两边的降序个数即可~
public class Solution {
public int candy(int[] ratings) {
if(ratings.length==0) return 0;
if(ratings.length==1) return 1;
int[] lowleft=new int[ratings.length];
int[] lowleft=new int[ratings.length];
int ret=0;
lowleft[0]=0;
for(int i=1;i<ratings.length;i++){
if(ratings[i-1]<ratings[i])
lowleft[i]=lowleft[i-1]+1;
//else if(ratings[i-1]==ratings[i])
lowleft[i]=lowleft[i-1];
else lowleft[i]=0;
}
lowright[ratings.length-1]=0;
for(int j=ratings.length-2;j>=0;j--){
if(ratings[j+1]<ratings[j])
lowright[j]=lowright[j+1]+1;
//else if(ratings[j+1]==ratings[j])
lowright[j]=lowleft[j+1];
else lowright[j]=0;
}
for(int i=0;i<ratings.length;i++){
ret=ret+1+Math.max(lowright[i],lowleft[i]);
}
return ret;
}
}