leetcode-643-easy

Maximum Average Subarray I

You are given an integer array nums consisting of n elements, and an integer k.

Find a contiguous subarray whose length is equal to k that has the maximum average value 
and return this value. Any answer with a calculation error less than 10-5 will be accepted.

Example 1:

Input: nums = [1,12,-5,-6,50,3], k = 4
Output: 12.75000
Explanation: Maximum average is (12 - 5 - 6 + 50) / 4 = 51 / 4 = 12.75
Example 2:

Input: nums = [5], k = 1
Output: 5.00000
Constraints:

n == nums.length
1 <= k <= n <= 105
-104 <= nums[i] <= 104

思路一：滑动窗口

    public double findMaxAverage(int[] nums, int k) {
        double sum = 0D;
        for (int i = 0; i <= k - 1; i++) {
            sum += nums[i];
        }

        double temp = sum;
        for (int i = 1; i + k - 1 < nums.length; i++) {
            temp = temp - nums[i - 1] + nums[i + k - 1];
            sum = Math.max(sum, temp);
        }

        return sum / k;
    }