643. Maximum Average Subarray I 最大子阵列平均数

Given an array consisting of n integers, find the contiguous subarray of given length k that has the maximum average value. And you need to output the maximum average value.

Example 1:

Input: [1,12,-5,-6,50,3], k = 4Output: 12.75Explanation: Maximum average is (12-5-6+50)/4 = 51/4 = 12.75


Note:

  1. 1 <= k <= n <= 30,000.

  2. Elements of the given array will be in the range [-10,000, 10,000].

 题意：求一个数组的最大子阵列平均数

 思路：运用动态规划，找出和最大、长度为k的子阵列


  1. class Solution(object):
  2.     def findMaxAverage(self, nums, k):
  3.         """
  4.         :type nums: List[int]
  5.         :type k: int
  6.         :rtype: float
  7.         """
  8.         sum = 0
  9.         curSum = 0
  10.         addNum = 0
  11.         for i in range(0, len(nums)):
  12.             if addNum < k:
  13.                 curSum += nums[i]
  14.                 sum = curSum
  15.                 addNum += 1
  16.             else:
  17.                 curSum = curSum - nums[i - k] + nums[i]
  18.                 sum = max(sum, curSum)
  19.         return sum * 1.0 / k




posted @ 2017-07-16 18:24  xiejunzhao  阅读(275)  评论(0)    收藏  举报