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

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;
    }
};