技術標籤：leetcode每日一題202102leetcode雙指標leetcode陣列

Problem

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.

Note:

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

Example

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

Solution

class Solution {
public:
    double findMaxAverage(vector<int>& nums, int k) {
        
        double res = -INT_MAX;
        double sum = 0;
        for(int i = 0,j=0;i<
 
nums.size();)
        {
            sum += nums[i];
            if(i-j+1 < k)
            {
                ++i;
            }
            else
            {
                res = max(res,sum/k);
                ++i;
                sum -= nums[j];
                ++j;
               
            }
 


        }

        return res;

    }
};