643. Maximum Average Subarray I

Posted 2020-10-07

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].

 

求连续k长的序列的最大平均值

C++（175ms）：

 1 class Solution {
 2 public:
 3     double findMaxAverage(vector<int>& nums, int k) {
 4         int sum = 0 ;
 5         int len = nums.size() ;
 6         for (int i = 0 ; i < k ; i++){
 7             sum += nums[i] ;
 8         }
 9         int Max = sum ;
10         int left = 0 ;
11         int right = k-1 ;
12         while(right < len-1){
13             sum = sum - nums[left++] + nums[++right] ;
14             if (sum > Max)
15                 Max = sum ;
16         }
17         return (double)Max/k ;
18     }
19 };