LeetCode Maximum Average Subarray I 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 = 4
Output: 12.75
Explanation: 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].

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给定一个数组，问长度为k的子数组的最大平均数是多少。简单题，因为平均数等于和除以k，k相同，也就相当于求长度为k的最长连续子串的和。 解法是维护一个长度为k的滑动窗口，求滑动窗口内的最大连续子数组的和，然后除以k。 代码如下： [cpp] class Solution { public: double findMaxAverage(vector<int>& nums, int k) { int n = nums.size(); if (n < k)return 0; int i = 0, sum = 0, ans = INT_MIN; for (int j = 0; j < k; ++j)sum += nums[j]; for (int j = k; j < n; ++j) { ans = max(ans, sum); sum += nums[j] – nums[i]; ++i; } ans = max(ans, sum); return ans / double(k); } }; [/cpp] 本代码提交AC，用时176MS。]]>