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)
}