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?

 

思想：确定变量分析法，先确定一个变量，然后进行分析. 先确保一侧满足条件，然后来调整另外一侧。

java代码：

1. public int candy(int[] ratings) {
2. int rlen = ratings.length;
3. if(rlen==0) return 0;
4. if(rlen==1) return 1;
5. int[] candy = new int[rlen];
6. for(int i=0;i<rlen;i++) {
7. candy[i] = 1;
8. }
9. for(int i=1;i<rlen;i++) {
10. if(ratings[i] > ratings[i-1]) {
11. candy[i] = candy[i-1] + 1;
12. }
13. }
14. for(int j=rlen-2;j>=0;j--) {
15. if(ratings[j] > ratings[j+1]) {
16. candy[j] = Math.max(candy[j],candy[j+1]+1);
17. }
18. }
19. int sum = 0;
20. for(int i=0;i<rlen;i++) {
21. sum+=candy[i];
22. }
23. return sum;
24. }