643. Maximum Average Subarray I
1. Description
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.
2. Example
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
3. Note
- 1 <= k <= n <= 30,000.
- Elements of the given array will be in the range [-10,000, 10,000].
4. Solutions
My Accepted Solution
n = i_nums.size()
Time complexity: O(n)
Space complexity: O(1)
// sliding windows
class Solution
{
public:
// double findMaxAverage(vector<int>& nums, int k)
double findMaxAverage(vector<int> &i_nums, int k)
{
double result = 0, sum = 0;
for(int i = 0; i < k; i++) sum += i_nums[i];
result = sum / k;
for(int i = k; i < i_nums.size(); i++)
{
sum += i_nums[i];
sum -= i_nums[i - k];
result = max(result, sum / k);
}
return result;
}
};