643. Maximum Average Subarray I

Posted 2020-10-10 andywu

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].

 题意：给定包含n个整数的数组，寻找长度为k的连续子数组的平均值的最大值。

思路，利用滑动窗口，依次比较窗口总和，最终记录最大值

 1     public double findMaxAverage(int[] nums, int k) {
 2  　　　　int maxSum = 0;
 3         for (int i = 0; i < k; i++) maxSum += nums[i];
 4         int sum = maxSum;
 5 
 6         for (int i = k; i < nums.length; i++) {
 7             sum += nums[i] - nums[i - k];
 8             maxSum = maxSum > sum ? maxSum : sum;
 9         }
10         return maxSum/1.0/k;
11     }