643. Maximum Average Subarray I -E

Q:

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].

 

A:

class Solution {
public:
    double findMaxAverage(vector<int>& nums, int k) {
        double sum = 0, maxSum =0;
        for(int i =0;i<k; ++i)
            sum += nums[i];
        maxSum= sum;
        for(int i =k;i<nums.size(); ++i){
            sum += nums[i]  - nums[i-k];
            maxSum = max(maxSum, sum);
        }
        return maxSum / k;
    }
};