643. Maximum Average Subarray I

Easy
​
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

解題

Runtime: 231 ms, faster than 81.42%
Memory Usage: 8.4 MB, less than 92.35%
func findMaxAverage(nums []int, k int) float64 {
now := 0
ans := math.MinInt64
for i:=0; i<len(nums); i++ {
now += nums[i]
if i == k-1 {
ans = now
}
if i >= k {
now -= nums[i-k]
}
if now > ans { ans = now }
}
fmt.Println(ans)
return float64(ans)/float64(k)
}