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[leetcode]Candy @ Python

原题地址:https://oj.leetcode.com/problems/candy/

题意:

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?

解题思路:求最吝啬的糖果分发数。先从前到后扫描一遍数组,如果序列递增,就+1;然后从后到前扫描一遍数组,序列递增,+1。保证最低谷(ratings最小)永远是1就可以了。

代码: 时间复杂度O(n),空间复杂度O(n)

class Solution:    # @param ratings, a list of integer    # @return an integer    def candy(self, ratings):        candyNum = [1] * len(ratings)        for i in range(1, len(ratings)):            if ratings[i - 1] < ratings[i]:                candyNum[i] = candyNum[i - 1] + 1        for i in range(len(ratings) - 2, -1, -1):            if ratings[i] > ratings[i + 1] and candyNum[i] <= candyNum[i + 1]:                candyNum[i] = candyNum[i + 1] + 1        return sum(candyNum)

 

[leetcode]Candy @ Python