643. Maximum Average Subarray I

题目

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 <= k <= n <= 30,000.
Elements of the given array will be in the range [-10,000, 10,000].

题目大意

给定 n 个整数，找出平均数最大且长度为 k 的连续子数组，并输出该最大平均数。

解题思路

简单题。循环一次，扫描数组过程中累加窗口大小为 k 的元素值。不断更新这个最大值。循环结束求出平均值即可。

代码

package leetcode

func findMaxAverage(nums []int, k int) float64 {
	sum := 0
	for _, v := range nums[:k] {
		sum += v
	}
	maxSum := sum
	for i := k; i < len(nums); i++ {
		sum = sum - nums[i-k] + nums[i]
		maxSum = max(maxSum, sum)
	}
	return float64(maxSum) / float64(k)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}