[Leetcode]643. Maximum Average Subarray I

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].

 

思路:把数组里每 K 个连续

class Solution {
    public double findMaxAverage(int[] nums, int k) {
        double sum = 0;
        for (int i = 0; i < k; i++)    
            sum += nums[i];
        double max = sum;
        for (int i = 0; i  < nums.length - k; i++){
            sum += nums[i+k] - nums[i];
            max = Math.max(max, sum);
        }
        return max / k;
    }
}

 

元素看作一个整体,然后一步一步地移动,比较这 K 个元素合与当前最大合 max 的大小。

 

posted @ 2017-11-21 17:37  SkyMelody  阅读(113)  评论(0编辑  收藏  举报