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# Maximum Average Subarray I

## 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.

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

## Solution

```cpp
class Solution {
public:
    double findMaxAverage(vector<int>& nums, int k) {
        int sum = accumulate(nums.begin(), nums.begin() + k, 0);
        int max_sum = sum;
        for(int i = k; i < nums.size(); ++i){
            sum = sum + nums[i] - nums[i - k];
            if(max_sum < sum)
                max_sum = sum;
        }
        return static_cast<double>(max_sum) / k;
    }
};
```